diff options
Diffstat (limited to '')
| -rw-r--r-- | fs/btrfs/extent-tree.c | 5920 |
1 files changed, 5920 insertions, 0 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c new file mode 100644 index 000000000..8f62e1710 --- /dev/null +++ b/fs/btrfs/extent-tree.c @@ -0,0 +1,5920 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2007 Oracle. All rights reserved. + */ + +#include <linux/sched.h> +#include <linux/sched/signal.h> +#include <linux/pagemap.h> +#include <linux/writeback.h> +#include <linux/blkdev.h> +#include <linux/sort.h> +#include <linux/rcupdate.h> +#include <linux/kthread.h> +#include <linux/slab.h> +#include <linux/ratelimit.h> +#include <linux/percpu_counter.h> +#include <linux/lockdep.h> +#include <linux/crc32c.h> +#include "misc.h" +#include "tree-log.h" +#include "disk-io.h" +#include "print-tree.h" +#include "volumes.h" +#include "raid56.h" +#include "locking.h" +#include "free-space-cache.h" +#include "free-space-tree.h" +#include "sysfs.h" +#include "qgroup.h" +#include "ref-verify.h" +#include "space-info.h" +#include "block-rsv.h" +#include "delalloc-space.h" +#include "block-group.h" +#include "discard.h" +#include "rcu-string.h" + +#undef SCRAMBLE_DELAYED_REFS + + +static int __btrfs_free_extent(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_node *node, u64 parent, + u64 root_objectid, u64 owner_objectid, + u64 owner_offset, int refs_to_drop, + struct btrfs_delayed_extent_op *extra_op); +static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op, + struct extent_buffer *leaf, + struct btrfs_extent_item *ei); +static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans, + u64 parent, u64 root_objectid, + u64 flags, u64 owner, u64 offset, + struct btrfs_key *ins, int ref_mod); +static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_node *node, + struct btrfs_delayed_extent_op *extent_op); +static int find_next_key(struct btrfs_path *path, int level, + struct btrfs_key *key); + +static int block_group_bits(struct btrfs_block_group *cache, u64 bits) +{ + return (cache->flags & bits) == bits; +} + +int btrfs_add_excluded_extent(struct btrfs_fs_info *fs_info, + u64 start, u64 num_bytes) +{ + u64 end = start + num_bytes - 1; + set_extent_bits(&fs_info->excluded_extents, start, end, + EXTENT_UPTODATE); + return 0; +} + +void btrfs_free_excluded_extents(struct btrfs_block_group *cache) +{ + struct btrfs_fs_info *fs_info = cache->fs_info; + u64 start, end; + + start = cache->start; + end = start + cache->length - 1; + + clear_extent_bits(&fs_info->excluded_extents, start, end, + EXTENT_UPTODATE); +} + +/* simple helper to search for an existing data extent at a given offset */ +int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len) +{ + int ret; + struct btrfs_key key; + struct btrfs_path *path; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + key.objectid = start; + key.offset = len; + key.type = BTRFS_EXTENT_ITEM_KEY; + ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0); + btrfs_free_path(path); + return ret; +} + +/* + * helper function to lookup reference count and flags of a tree block. + * + * the head node for delayed ref is used to store the sum of all the + * reference count modifications queued up in the rbtree. the head + * node may also store the extent flags to set. This way you can check + * to see what the reference count and extent flags would be if all of + * the delayed refs are not processed. + */ +int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans, + struct btrfs_fs_info *fs_info, u64 bytenr, + u64 offset, int metadata, u64 *refs, u64 *flags) +{ + struct btrfs_delayed_ref_head *head; + struct btrfs_delayed_ref_root *delayed_refs; + struct btrfs_path *path; + struct btrfs_extent_item *ei; + struct extent_buffer *leaf; + struct btrfs_key key; + u32 item_size; + u64 num_refs; + u64 extent_flags; + int ret; + + /* + * If we don't have skinny metadata, don't bother doing anything + * different + */ + if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) { + offset = fs_info->nodesize; + metadata = 0; + } + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + if (!trans) { + path->skip_locking = 1; + path->search_commit_root = 1; + } + +search_again: + key.objectid = bytenr; + key.offset = offset; + if (metadata) + key.type = BTRFS_METADATA_ITEM_KEY; + else + key.type = BTRFS_EXTENT_ITEM_KEY; + + ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0); + if (ret < 0) + goto out_free; + + if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) { + if (path->slots[0]) { + path->slots[0]--; + btrfs_item_key_to_cpu(path->nodes[0], &key, + path->slots[0]); + if (key.objectid == bytenr && + key.type == BTRFS_EXTENT_ITEM_KEY && + key.offset == fs_info->nodesize) + ret = 0; + } + } + + if (ret == 0) { + leaf = path->nodes[0]; + item_size = btrfs_item_size_nr(leaf, path->slots[0]); + if (item_size >= sizeof(*ei)) { + ei = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_extent_item); + num_refs = btrfs_extent_refs(leaf, ei); + extent_flags = btrfs_extent_flags(leaf, ei); + } else { + ret = -EINVAL; + btrfs_print_v0_err(fs_info); + if (trans) + btrfs_abort_transaction(trans, ret); + else + btrfs_handle_fs_error(fs_info, ret, NULL); + + goto out_free; + } + + BUG_ON(num_refs == 0); + } else { + num_refs = 0; + extent_flags = 0; + ret = 0; + } + + if (!trans) + goto out; + + delayed_refs = &trans->transaction->delayed_refs; + spin_lock(&delayed_refs->lock); + head = btrfs_find_delayed_ref_head(delayed_refs, bytenr); + if (head) { + if (!mutex_trylock(&head->mutex)) { + refcount_inc(&head->refs); + spin_unlock(&delayed_refs->lock); + + btrfs_release_path(path); + + /* + * Mutex was contended, block until it's released and try + * again + */ + mutex_lock(&head->mutex); + mutex_unlock(&head->mutex); + btrfs_put_delayed_ref_head(head); + goto search_again; + } + spin_lock(&head->lock); + if (head->extent_op && head->extent_op->update_flags) + extent_flags |= head->extent_op->flags_to_set; + else + BUG_ON(num_refs == 0); + + num_refs += head->ref_mod; + spin_unlock(&head->lock); + mutex_unlock(&head->mutex); + } + spin_unlock(&delayed_refs->lock); +out: + WARN_ON(num_refs == 0); + if (refs) + *refs = num_refs; + if (flags) + *flags = extent_flags; +out_free: + btrfs_free_path(path); + return ret; +} + +/* + * Back reference rules. Back refs have three main goals: + * + * 1) differentiate between all holders of references to an extent so that + * when a reference is dropped we can make sure it was a valid reference + * before freeing the extent. + * + * 2) Provide enough information to quickly find the holders of an extent + * if we notice a given block is corrupted or bad. + * + * 3) Make it easy to migrate blocks for FS shrinking or storage pool + * maintenance. This is actually the same as #2, but with a slightly + * different use case. + * + * There are two kinds of back refs. The implicit back refs is optimized + * for pointers in non-shared tree blocks. For a given pointer in a block, + * back refs of this kind provide information about the block's owner tree + * and the pointer's key. These information allow us to find the block by + * b-tree searching. The full back refs is for pointers in tree blocks not + * referenced by their owner trees. The location of tree block is recorded + * in the back refs. Actually the full back refs is generic, and can be + * used in all cases the implicit back refs is used. The major shortcoming + * of the full back refs is its overhead. Every time a tree block gets + * COWed, we have to update back refs entry for all pointers in it. + * + * For a newly allocated tree block, we use implicit back refs for + * pointers in it. This means most tree related operations only involve + * implicit back refs. For a tree block created in old transaction, the + * only way to drop a reference to it is COW it. So we can detect the + * event that tree block loses its owner tree's reference and do the + * back refs conversion. + * + * When a tree block is COWed through a tree, there are four cases: + * + * The reference count of the block is one and the tree is the block's + * owner tree. Nothing to do in this case. + * + * The reference count of the block is one and the tree is not the + * block's owner tree. In this case, full back refs is used for pointers + * in the block. Remove these full back refs, add implicit back refs for + * every pointers in the new block. + * + * The reference count of the block is greater than one and the tree is + * the block's owner tree. In this case, implicit back refs is used for + * pointers in the block. Add full back refs for every pointers in the + * block, increase lower level extents' reference counts. The original + * implicit back refs are entailed to the new block. + * + * The reference count of the block is greater than one and the tree is + * not the block's owner tree. Add implicit back refs for every pointer in + * the new block, increase lower level extents' reference count. + * + * Back Reference Key composing: + * + * The key objectid corresponds to the first byte in the extent, + * The key type is used to differentiate between types of back refs. + * There are different meanings of the key offset for different types + * of back refs. + * + * File extents can be referenced by: + * + * - multiple snapshots, subvolumes, or different generations in one subvol + * - different files inside a single subvolume + * - different offsets inside a file (bookend extents in file.c) + * + * The extent ref structure for the implicit back refs has fields for: + * + * - Objectid of the subvolume root + * - objectid of the file holding the reference + * - original offset in the file + * - how many bookend extents + * + * The key offset for the implicit back refs is hash of the first + * three fields. + * + * The extent ref structure for the full back refs has field for: + * + * - number of pointers in the tree leaf + * + * The key offset for the implicit back refs is the first byte of + * the tree leaf + * + * When a file extent is allocated, The implicit back refs is used. + * the fields are filled in: + * + * (root_key.objectid, inode objectid, offset in file, 1) + * + * When a file extent is removed file truncation, we find the + * corresponding implicit back refs and check the following fields: + * + * (btrfs_header_owner(leaf), inode objectid, offset in file) + * + * Btree extents can be referenced by: + * + * - Different subvolumes + * + * Both the implicit back refs and the full back refs for tree blocks + * only consist of key. The key offset for the implicit back refs is + * objectid of block's owner tree. The key offset for the full back refs + * is the first byte of parent block. + * + * When implicit back refs is used, information about the lowest key and + * level of the tree block are required. These information are stored in + * tree block info structure. + */ + +/* + * is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required, + * is_data == BTRFS_REF_TYPE_DATA, data type is requiried, + * is_data == BTRFS_REF_TYPE_ANY, either type is OK. + */ +int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb, + struct btrfs_extent_inline_ref *iref, + enum btrfs_inline_ref_type is_data) +{ + int type = btrfs_extent_inline_ref_type(eb, iref); + u64 offset = btrfs_extent_inline_ref_offset(eb, iref); + + if (type == BTRFS_TREE_BLOCK_REF_KEY || + type == BTRFS_SHARED_BLOCK_REF_KEY || + type == BTRFS_SHARED_DATA_REF_KEY || + type == BTRFS_EXTENT_DATA_REF_KEY) { + if (is_data == BTRFS_REF_TYPE_BLOCK) { + if (type == BTRFS_TREE_BLOCK_REF_KEY) + return type; + if (type == BTRFS_SHARED_BLOCK_REF_KEY) { + ASSERT(eb->fs_info); + /* + * Every shared one has parent tree block, + * which must be aligned to sector size. + */ + if (offset && + IS_ALIGNED(offset, eb->fs_info->sectorsize)) + return type; + } + } else if (is_data == BTRFS_REF_TYPE_DATA) { + if (type == BTRFS_EXTENT_DATA_REF_KEY) + return type; + if (type == BTRFS_SHARED_DATA_REF_KEY) { + ASSERT(eb->fs_info); + /* + * Every shared one has parent tree block, + * which must be aligned to sector size. + */ + if (offset && + IS_ALIGNED(offset, eb->fs_info->sectorsize)) + return type; + } + } else { + ASSERT(is_data == BTRFS_REF_TYPE_ANY); + return type; + } + } + + btrfs_print_leaf((struct extent_buffer *)eb); + btrfs_err(eb->fs_info, + "eb %llu iref 0x%lx invalid extent inline ref type %d", + eb->start, (unsigned long)iref, type); + WARN_ON(1); + + return BTRFS_REF_TYPE_INVALID; +} + +u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset) +{ + u32 high_crc = ~(u32)0; + u32 low_crc = ~(u32)0; + __le64 lenum; + + lenum = cpu_to_le64(root_objectid); + high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum)); + lenum = cpu_to_le64(owner); + low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum)); + lenum = cpu_to_le64(offset); + low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum)); + + return ((u64)high_crc << 31) ^ (u64)low_crc; +} + +static u64 hash_extent_data_ref_item(struct extent_buffer *leaf, + struct btrfs_extent_data_ref *ref) +{ + return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref), + btrfs_extent_data_ref_objectid(leaf, ref), + btrfs_extent_data_ref_offset(leaf, ref)); +} + +static int match_extent_data_ref(struct extent_buffer *leaf, + struct btrfs_extent_data_ref *ref, + u64 root_objectid, u64 owner, u64 offset) +{ + if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid || + btrfs_extent_data_ref_objectid(leaf, ref) != owner || + btrfs_extent_data_ref_offset(leaf, ref) != offset) + return 0; + return 1; +} + +static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans, + struct btrfs_path *path, + u64 bytenr, u64 parent, + u64 root_objectid, + u64 owner, u64 offset) +{ + struct btrfs_root *root = trans->fs_info->extent_root; + struct btrfs_key key; + struct btrfs_extent_data_ref *ref; + struct extent_buffer *leaf; + u32 nritems; + int ret; + int recow; + int err = -ENOENT; + + key.objectid = bytenr; + if (parent) { + key.type = BTRFS_SHARED_DATA_REF_KEY; + key.offset = parent; + } else { + key.type = BTRFS_EXTENT_DATA_REF_KEY; + key.offset = hash_extent_data_ref(root_objectid, + owner, offset); + } +again: + recow = 0; + ret = btrfs_search_slot(trans, root, &key, path, -1, 1); + if (ret < 0) { + err = ret; + goto fail; + } + + if (parent) { + if (!ret) + return 0; + goto fail; + } + + leaf = path->nodes[0]; + nritems = btrfs_header_nritems(leaf); + while (1) { + if (path->slots[0] >= nritems) { + ret = btrfs_next_leaf(root, path); + if (ret < 0) + err = ret; + if (ret) + goto fail; + + leaf = path->nodes[0]; + nritems = btrfs_header_nritems(leaf); + recow = 1; + } + + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + if (key.objectid != bytenr || + key.type != BTRFS_EXTENT_DATA_REF_KEY) + goto fail; + + ref = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_extent_data_ref); + + if (match_extent_data_ref(leaf, ref, root_objectid, + owner, offset)) { + if (recow) { + btrfs_release_path(path); + goto again; + } + err = 0; + break; + } + path->slots[0]++; + } +fail: + return err; +} + +static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans, + struct btrfs_path *path, + u64 bytenr, u64 parent, + u64 root_objectid, u64 owner, + u64 offset, int refs_to_add) +{ + struct btrfs_root *root = trans->fs_info->extent_root; + struct btrfs_key key; + struct extent_buffer *leaf; + u32 size; + u32 num_refs; + int ret; + + key.objectid = bytenr; + if (parent) { + key.type = BTRFS_SHARED_DATA_REF_KEY; + key.offset = parent; + size = sizeof(struct btrfs_shared_data_ref); + } else { + key.type = BTRFS_EXTENT_DATA_REF_KEY; + key.offset = hash_extent_data_ref(root_objectid, + owner, offset); + size = sizeof(struct btrfs_extent_data_ref); + } + + ret = btrfs_insert_empty_item(trans, root, path, &key, size); + if (ret && ret != -EEXIST) + goto fail; + + leaf = path->nodes[0]; + if (parent) { + struct btrfs_shared_data_ref *ref; + ref = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_shared_data_ref); + if (ret == 0) { + btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add); + } else { + num_refs = btrfs_shared_data_ref_count(leaf, ref); + num_refs += refs_to_add; + btrfs_set_shared_data_ref_count(leaf, ref, num_refs); + } + } else { + struct btrfs_extent_data_ref *ref; + while (ret == -EEXIST) { + ref = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_extent_data_ref); + if (match_extent_data_ref(leaf, ref, root_objectid, + owner, offset)) + break; + btrfs_release_path(path); + key.offset++; + ret = btrfs_insert_empty_item(trans, root, path, &key, + size); + if (ret && ret != -EEXIST) + goto fail; + + leaf = path->nodes[0]; + } + ref = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_extent_data_ref); + if (ret == 0) { + btrfs_set_extent_data_ref_root(leaf, ref, + root_objectid); + btrfs_set_extent_data_ref_objectid(leaf, ref, owner); + btrfs_set_extent_data_ref_offset(leaf, ref, offset); + btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add); + } else { + num_refs = btrfs_extent_data_ref_count(leaf, ref); + num_refs += refs_to_add; + btrfs_set_extent_data_ref_count(leaf, ref, num_refs); + } + } + btrfs_mark_buffer_dirty(leaf); + ret = 0; +fail: + btrfs_release_path(path); + return ret; +} + +static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans, + struct btrfs_path *path, + int refs_to_drop, int *last_ref) +{ + struct btrfs_key key; + struct btrfs_extent_data_ref *ref1 = NULL; + struct btrfs_shared_data_ref *ref2 = NULL; + struct extent_buffer *leaf; + u32 num_refs = 0; + int ret = 0; + + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + + if (key.type == BTRFS_EXTENT_DATA_REF_KEY) { + ref1 = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_extent_data_ref); + num_refs = btrfs_extent_data_ref_count(leaf, ref1); + } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) { + ref2 = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_shared_data_ref); + num_refs = btrfs_shared_data_ref_count(leaf, ref2); + } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) { + btrfs_print_v0_err(trans->fs_info); + btrfs_abort_transaction(trans, -EINVAL); + return -EINVAL; + } else { + BUG(); + } + + BUG_ON(num_refs < refs_to_drop); + num_refs -= refs_to_drop; + + if (num_refs == 0) { + ret = btrfs_del_item(trans, trans->fs_info->extent_root, path); + *last_ref = 1; + } else { + if (key.type == BTRFS_EXTENT_DATA_REF_KEY) + btrfs_set_extent_data_ref_count(leaf, ref1, num_refs); + else if (key.type == BTRFS_SHARED_DATA_REF_KEY) + btrfs_set_shared_data_ref_count(leaf, ref2, num_refs); + btrfs_mark_buffer_dirty(leaf); + } + return ret; +} + +static noinline u32 extent_data_ref_count(struct btrfs_path *path, + struct btrfs_extent_inline_ref *iref) +{ + struct btrfs_key key; + struct extent_buffer *leaf; + struct btrfs_extent_data_ref *ref1; + struct btrfs_shared_data_ref *ref2; + u32 num_refs = 0; + int type; + + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + + BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY); + if (iref) { + /* + * If type is invalid, we should have bailed out earlier than + * this call. + */ + type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA); + ASSERT(type != BTRFS_REF_TYPE_INVALID); + if (type == BTRFS_EXTENT_DATA_REF_KEY) { + ref1 = (struct btrfs_extent_data_ref *)(&iref->offset); + num_refs = btrfs_extent_data_ref_count(leaf, ref1); + } else { + ref2 = (struct btrfs_shared_data_ref *)(iref + 1); + num_refs = btrfs_shared_data_ref_count(leaf, ref2); + } + } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) { + ref1 = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_extent_data_ref); + num_refs = btrfs_extent_data_ref_count(leaf, ref1); + } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) { + ref2 = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_shared_data_ref); + num_refs = btrfs_shared_data_ref_count(leaf, ref2); + } else { + WARN_ON(1); + } + return num_refs; +} + +static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans, + struct btrfs_path *path, + u64 bytenr, u64 parent, + u64 root_objectid) +{ + struct btrfs_root *root = trans->fs_info->extent_root; + struct btrfs_key key; + int ret; + + key.objectid = bytenr; + if (parent) { + key.type = BTRFS_SHARED_BLOCK_REF_KEY; + key.offset = parent; + } else { + key.type = BTRFS_TREE_BLOCK_REF_KEY; + key.offset = root_objectid; + } + + ret = btrfs_search_slot(trans, root, &key, path, -1, 1); + if (ret > 0) + ret = -ENOENT; + return ret; +} + +static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans, + struct btrfs_path *path, + u64 bytenr, u64 parent, + u64 root_objectid) +{ + struct btrfs_key key; + int ret; + + key.objectid = bytenr; + if (parent) { + key.type = BTRFS_SHARED_BLOCK_REF_KEY; + key.offset = parent; + } else { + key.type = BTRFS_TREE_BLOCK_REF_KEY; + key.offset = root_objectid; + } + + ret = btrfs_insert_empty_item(trans, trans->fs_info->extent_root, + path, &key, 0); + btrfs_release_path(path); + return ret; +} + +static inline int extent_ref_type(u64 parent, u64 owner) +{ + int type; + if (owner < BTRFS_FIRST_FREE_OBJECTID) { + if (parent > 0) + type = BTRFS_SHARED_BLOCK_REF_KEY; + else + type = BTRFS_TREE_BLOCK_REF_KEY; + } else { + if (parent > 0) + type = BTRFS_SHARED_DATA_REF_KEY; + else + type = BTRFS_EXTENT_DATA_REF_KEY; + } + return type; +} + +static int find_next_key(struct btrfs_path *path, int level, + struct btrfs_key *key) + +{ + for (; level < BTRFS_MAX_LEVEL; level++) { + if (!path->nodes[level]) + break; + if (path->slots[level] + 1 >= + btrfs_header_nritems(path->nodes[level])) + continue; + if (level == 0) + btrfs_item_key_to_cpu(path->nodes[level], key, + path->slots[level] + 1); + else + btrfs_node_key_to_cpu(path->nodes[level], key, + path->slots[level] + 1); + return 0; + } + return 1; +} + +/* + * look for inline back ref. if back ref is found, *ref_ret is set + * to the address of inline back ref, and 0 is returned. + * + * if back ref isn't found, *ref_ret is set to the address where it + * should be inserted, and -ENOENT is returned. + * + * if insert is true and there are too many inline back refs, the path + * points to the extent item, and -EAGAIN is returned. + * + * NOTE: inline back refs are ordered in the same way that back ref + * items in the tree are ordered. + */ +static noinline_for_stack +int lookup_inline_extent_backref(struct btrfs_trans_handle *trans, + struct btrfs_path *path, + struct btrfs_extent_inline_ref **ref_ret, + u64 bytenr, u64 num_bytes, + u64 parent, u64 root_objectid, + u64 owner, u64 offset, int insert) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_root *root = fs_info->extent_root; + struct btrfs_key key; + struct extent_buffer *leaf; + struct btrfs_extent_item *ei; + struct btrfs_extent_inline_ref *iref; + u64 flags; + u64 item_size; + unsigned long ptr; + unsigned long end; + int extra_size; + int type; + int want; + int ret; + int err = 0; + bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA); + int needed; + + key.objectid = bytenr; + key.type = BTRFS_EXTENT_ITEM_KEY; + key.offset = num_bytes; + + want = extent_ref_type(parent, owner); + if (insert) { + extra_size = btrfs_extent_inline_ref_size(want); + path->keep_locks = 1; + } else + extra_size = -1; + + /* + * Owner is our level, so we can just add one to get the level for the + * block we are interested in. + */ + if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) { + key.type = BTRFS_METADATA_ITEM_KEY; + key.offset = owner; + } + +again: + ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1); + if (ret < 0) { + err = ret; + goto out; + } + + /* + * We may be a newly converted file system which still has the old fat + * extent entries for metadata, so try and see if we have one of those. + */ + if (ret > 0 && skinny_metadata) { + skinny_metadata = false; + if (path->slots[0]) { + path->slots[0]--; + btrfs_item_key_to_cpu(path->nodes[0], &key, + path->slots[0]); + if (key.objectid == bytenr && + key.type == BTRFS_EXTENT_ITEM_KEY && + key.offset == num_bytes) + ret = 0; + } + if (ret) { + key.objectid = bytenr; + key.type = BTRFS_EXTENT_ITEM_KEY; + key.offset = num_bytes; + btrfs_release_path(path); + goto again; + } + } + + if (ret && !insert) { + err = -ENOENT; + goto out; + } else if (WARN_ON(ret)) { + btrfs_print_leaf(path->nodes[0]); + btrfs_err(fs_info, +"extent item not found for insert, bytenr %llu num_bytes %llu parent %llu root_objectid %llu owner %llu offset %llu", + bytenr, num_bytes, parent, root_objectid, owner, + offset); + err = -EIO; + goto out; + } + + leaf = path->nodes[0]; + item_size = btrfs_item_size_nr(leaf, path->slots[0]); + if (unlikely(item_size < sizeof(*ei))) { + err = -EINVAL; + btrfs_print_v0_err(fs_info); + btrfs_abort_transaction(trans, err); + goto out; + } + + ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); + flags = btrfs_extent_flags(leaf, ei); + + ptr = (unsigned long)(ei + 1); + end = (unsigned long)ei + item_size; + + if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) { + ptr += sizeof(struct btrfs_tree_block_info); + BUG_ON(ptr > end); + } + + if (owner >= BTRFS_FIRST_FREE_OBJECTID) + needed = BTRFS_REF_TYPE_DATA; + else + needed = BTRFS_REF_TYPE_BLOCK; + + err = -ENOENT; + while (1) { + if (ptr >= end) { + WARN_ON(ptr > end); + break; + } + iref = (struct btrfs_extent_inline_ref *)ptr; + type = btrfs_get_extent_inline_ref_type(leaf, iref, needed); + if (type == BTRFS_REF_TYPE_INVALID) { + err = -EUCLEAN; + goto out; + } + + if (want < type) + break; + if (want > type) { + ptr += btrfs_extent_inline_ref_size(type); + continue; + } + + if (type == BTRFS_EXTENT_DATA_REF_KEY) { + struct btrfs_extent_data_ref *dref; + dref = (struct btrfs_extent_data_ref *)(&iref->offset); + if (match_extent_data_ref(leaf, dref, root_objectid, + owner, offset)) { + err = 0; + break; + } + if (hash_extent_data_ref_item(leaf, dref) < + hash_extent_data_ref(root_objectid, owner, offset)) + break; + } else { + u64 ref_offset; + ref_offset = btrfs_extent_inline_ref_offset(leaf, iref); + if (parent > 0) { + if (parent == ref_offset) { + err = 0; + break; + } + if (ref_offset < parent) + break; + } else { + if (root_objectid == ref_offset) { + err = 0; + break; + } + if (ref_offset < root_objectid) + break; + } + } + ptr += btrfs_extent_inline_ref_size(type); + } + if (err == -ENOENT && insert) { + if (item_size + extra_size >= + BTRFS_MAX_EXTENT_ITEM_SIZE(root)) { + err = -EAGAIN; + goto out; + } + /* + * To add new inline back ref, we have to make sure + * there is no corresponding back ref item. + * For simplicity, we just do not add new inline back + * ref if there is any kind of item for this block + */ + if (find_next_key(path, 0, &key) == 0 && + key.objectid == bytenr && + key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) { + err = -EAGAIN; + goto out; + } + } + *ref_ret = (struct btrfs_extent_inline_ref *)ptr; +out: + if (insert) { + path->keep_locks = 0; + btrfs_unlock_up_safe(path, 1); + } + return err; +} + +/* + * helper to add new inline back ref + */ +static noinline_for_stack +void setup_inline_extent_backref(struct btrfs_fs_info *fs_info, + struct btrfs_path *path, + struct btrfs_extent_inline_ref *iref, + u64 parent, u64 root_objectid, + u64 owner, u64 offset, int refs_to_add, + struct btrfs_delayed_extent_op *extent_op) +{ + struct extent_buffer *leaf; + struct btrfs_extent_item *ei; + unsigned long ptr; + unsigned long end; + unsigned long item_offset; + u64 refs; + int size; + int type; + + leaf = path->nodes[0]; + ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); + item_offset = (unsigned long)iref - (unsigned long)ei; + + type = extent_ref_type(parent, owner); + size = btrfs_extent_inline_ref_size(type); + + btrfs_extend_item(path, size); + + ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); + refs = btrfs_extent_refs(leaf, ei); + refs += refs_to_add; + btrfs_set_extent_refs(leaf, ei, refs); + if (extent_op) + __run_delayed_extent_op(extent_op, leaf, ei); + + ptr = (unsigned long)ei + item_offset; + end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]); + if (ptr < end - size) + memmove_extent_buffer(leaf, ptr + size, ptr, + end - size - ptr); + + iref = (struct btrfs_extent_inline_ref *)ptr; + btrfs_set_extent_inline_ref_type(leaf, iref, type); + if (type == BTRFS_EXTENT_DATA_REF_KEY) { + struct btrfs_extent_data_ref *dref; + dref = (struct btrfs_extent_data_ref *)(&iref->offset); + btrfs_set_extent_data_ref_root(leaf, dref, root_objectid); + btrfs_set_extent_data_ref_objectid(leaf, dref, owner); + btrfs_set_extent_data_ref_offset(leaf, dref, offset); + btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add); + } else if (type == BTRFS_SHARED_DATA_REF_KEY) { + struct btrfs_shared_data_ref *sref; + sref = (struct btrfs_shared_data_ref *)(iref + 1); + btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add); + btrfs_set_extent_inline_ref_offset(leaf, iref, parent); + } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) { + btrfs_set_extent_inline_ref_offset(leaf, iref, parent); + } else { + btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid); + } + btrfs_mark_buffer_dirty(leaf); +} + +static int lookup_extent_backref(struct btrfs_trans_handle *trans, + struct btrfs_path *path, + struct btrfs_extent_inline_ref **ref_ret, + u64 bytenr, u64 num_bytes, u64 parent, + u64 root_objectid, u64 owner, u64 offset) +{ + int ret; + + ret = lookup_inline_extent_backref(trans, path, ref_ret, bytenr, + num_bytes, parent, root_objectid, + owner, offset, 0); + if (ret != -ENOENT) + return ret; + + btrfs_release_path(path); + *ref_ret = NULL; + + if (owner < BTRFS_FIRST_FREE_OBJECTID) { + ret = lookup_tree_block_ref(trans, path, bytenr, parent, + root_objectid); + } else { + ret = lookup_extent_data_ref(trans, path, bytenr, parent, + root_objectid, owner, offset); + } + return ret; +} + +/* + * helper to update/remove inline back ref + */ +static noinline_for_stack +void update_inline_extent_backref(struct btrfs_path *path, + struct btrfs_extent_inline_ref *iref, + int refs_to_mod, + struct btrfs_delayed_extent_op *extent_op, + int *last_ref) +{ + struct extent_buffer *leaf = path->nodes[0]; + struct btrfs_extent_item *ei; + struct btrfs_extent_data_ref *dref = NULL; + struct btrfs_shared_data_ref *sref = NULL; + unsigned long ptr; + unsigned long end; + u32 item_size; + int size; + int type; + u64 refs; + + ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); + refs = btrfs_extent_refs(leaf, ei); + WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0); + refs += refs_to_mod; + btrfs_set_extent_refs(leaf, ei, refs); + if (extent_op) + __run_delayed_extent_op(extent_op, leaf, ei); + + /* + * If type is invalid, we should have bailed out after + * lookup_inline_extent_backref(). + */ + type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY); + ASSERT(type != BTRFS_REF_TYPE_INVALID); + + if (type == BTRFS_EXTENT_DATA_REF_KEY) { + dref = (struct btrfs_extent_data_ref *)(&iref->offset); + refs = btrfs_extent_data_ref_count(leaf, dref); + } else if (type == BTRFS_SHARED_DATA_REF_KEY) { + sref = (struct btrfs_shared_data_ref *)(iref + 1); + refs = btrfs_shared_data_ref_count(leaf, sref); + } else { + refs = 1; + BUG_ON(refs_to_mod != -1); + } + + BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod); + refs += refs_to_mod; + + if (refs > 0) { + if (type == BTRFS_EXTENT_DATA_REF_KEY) + btrfs_set_extent_data_ref_count(leaf, dref, refs); + else + btrfs_set_shared_data_ref_count(leaf, sref, refs); + } else { + *last_ref = 1; + size = btrfs_extent_inline_ref_size(type); + item_size = btrfs_item_size_nr(leaf, path->slots[0]); + ptr = (unsigned long)iref; + end = (unsigned long)ei + item_size; + if (ptr + size < end) + memmove_extent_buffer(leaf, ptr, ptr + size, + end - ptr - size); + item_size -= size; + btrfs_truncate_item(path, item_size, 1); + } + btrfs_mark_buffer_dirty(leaf); +} + +static noinline_for_stack +int insert_inline_extent_backref(struct btrfs_trans_handle *trans, + struct btrfs_path *path, + u64 bytenr, u64 num_bytes, u64 parent, + u64 root_objectid, u64 owner, + u64 offset, int refs_to_add, + struct btrfs_delayed_extent_op *extent_op) +{ + struct btrfs_extent_inline_ref *iref; + int ret; + + ret = lookup_inline_extent_backref(trans, path, &iref, bytenr, + num_bytes, parent, root_objectid, + owner, offset, 1); + if (ret == 0) { + /* + * We're adding refs to a tree block we already own, this + * should not happen at all. + */ + if (owner < BTRFS_FIRST_FREE_OBJECTID) { + btrfs_crit(trans->fs_info, +"adding refs to an existing tree ref, bytenr %llu num_bytes %llu root_objectid %llu", + bytenr, num_bytes, root_objectid); + if (IS_ENABLED(CONFIG_BTRFS_DEBUG)) { + WARN_ON(1); + btrfs_crit(trans->fs_info, + "path->slots[0]=%d path->nodes[0]:", path->slots[0]); + btrfs_print_leaf(path->nodes[0]); + } + return -EUCLEAN; + } + update_inline_extent_backref(path, iref, refs_to_add, + extent_op, NULL); + } else if (ret == -ENOENT) { + setup_inline_extent_backref(trans->fs_info, path, iref, parent, + root_objectid, owner, offset, + refs_to_add, extent_op); + ret = 0; + } + return ret; +} + +static int remove_extent_backref(struct btrfs_trans_handle *trans, + struct btrfs_path *path, + struct btrfs_extent_inline_ref *iref, + int refs_to_drop, int is_data, int *last_ref) +{ + int ret = 0; + + BUG_ON(!is_data && refs_to_drop != 1); + if (iref) { + update_inline_extent_backref(path, iref, -refs_to_drop, NULL, + last_ref); + } else if (is_data) { + ret = remove_extent_data_ref(trans, path, refs_to_drop, + last_ref); + } else { + *last_ref = 1; + ret = btrfs_del_item(trans, trans->fs_info->extent_root, path); + } + return ret; +} + +static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len, + u64 *discarded_bytes) +{ + int j, ret = 0; + u64 bytes_left, end; + u64 aligned_start = ALIGN(start, 1 << 9); + + if (WARN_ON(start != aligned_start)) { + len -= aligned_start - start; + len = round_down(len, 1 << 9); + start = aligned_start; + } + + *discarded_bytes = 0; + + if (!len) + return 0; + + end = start + len; + bytes_left = len; + + /* Skip any superblocks on this device. */ + for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) { + u64 sb_start = btrfs_sb_offset(j); + u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE; + u64 size = sb_start - start; + + if (!in_range(sb_start, start, bytes_left) && + !in_range(sb_end, start, bytes_left) && + !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE)) + continue; + + /* + * Superblock spans beginning of range. Adjust start and + * try again. + */ + if (sb_start <= start) { + start += sb_end - start; + if (start > end) { + bytes_left = 0; + break; + } + bytes_left = end - start; + continue; + } + + if (size) { + ret = blkdev_issue_discard(bdev, start >> 9, size >> 9, + GFP_NOFS, 0); + if (!ret) + *discarded_bytes += size; + else if (ret != -EOPNOTSUPP) + return ret; + } + + start = sb_end; + if (start > end) { + bytes_left = 0; + break; + } + bytes_left = end - start; + } + + if (bytes_left) { + ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9, + GFP_NOFS, 0); + if (!ret) + *discarded_bytes += bytes_left; + } + return ret; +} + +int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr, + u64 num_bytes, u64 *actual_bytes) +{ + int ret = 0; + u64 discarded_bytes = 0; + u64 end = bytenr + num_bytes; + u64 cur = bytenr; + struct btrfs_bio *bbio = NULL; + + + /* + * Avoid races with device replace and make sure our bbio has devices + * associated to its stripes that don't go away while we are discarding. + */ + btrfs_bio_counter_inc_blocked(fs_info); + while (cur < end) { + struct btrfs_bio_stripe *stripe; + int i; + + num_bytes = end - cur; + /* Tell the block device(s) that the sectors can be discarded */ + ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, cur, + &num_bytes, &bbio, 0); + /* + * Error can be -ENOMEM, -ENOENT (no such chunk mapping) or + * -EOPNOTSUPP. For any such error, @num_bytes is not updated, + * thus we can't continue anyway. + */ + if (ret < 0) + goto out; + + stripe = bbio->stripes; + for (i = 0; i < bbio->num_stripes; i++, stripe++) { + u64 bytes; + struct request_queue *req_q; + struct btrfs_device *device = stripe->dev; + + if (!device->bdev) { + ASSERT(btrfs_test_opt(fs_info, DEGRADED)); + continue; + } + req_q = bdev_get_queue(device->bdev); + if (!blk_queue_discard(req_q)) + continue; + + if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state)) + continue; + + ret = btrfs_issue_discard(device->bdev, + stripe->physical, + stripe->length, + &bytes); + if (!ret) { + discarded_bytes += bytes; + } else if (ret != -EOPNOTSUPP) { + /* + * Logic errors or -ENOMEM, or -EIO, but + * unlikely to happen. + * + * And since there are two loops, explicitly + * go to out to avoid confusion. + */ + btrfs_put_bbio(bbio); + goto out; + } + + /* + * Just in case we get back EOPNOTSUPP for some reason, + * just ignore the return value so we don't screw up + * people calling discard_extent. + */ + ret = 0; + } + btrfs_put_bbio(bbio); + cur += num_bytes; + } +out: + btrfs_bio_counter_dec(fs_info); + + if (actual_bytes) + *actual_bytes = discarded_bytes; + + + if (ret == -EOPNOTSUPP) + ret = 0; + return ret; +} + +/* Can return -ENOMEM */ +int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans, + struct btrfs_ref *generic_ref) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + int ret; + + ASSERT(generic_ref->type != BTRFS_REF_NOT_SET && + generic_ref->action); + BUG_ON(generic_ref->type == BTRFS_REF_METADATA && + generic_ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID); + + if (generic_ref->type == BTRFS_REF_METADATA) + ret = btrfs_add_delayed_tree_ref(trans, generic_ref, NULL); + else + ret = btrfs_add_delayed_data_ref(trans, generic_ref, 0); + + btrfs_ref_tree_mod(fs_info, generic_ref); + + return ret; +} + +/* + * __btrfs_inc_extent_ref - insert backreference for a given extent + * + * The counterpart is in __btrfs_free_extent(), with examples and more details + * how it works. + * + * @trans: Handle of transaction + * + * @node: The delayed ref node used to get the bytenr/length for + * extent whose references are incremented. + * + * @parent: If this is a shared extent (BTRFS_SHARED_DATA_REF_KEY/ + * BTRFS_SHARED_BLOCK_REF_KEY) then it holds the logical + * bytenr of the parent block. Since new extents are always + * created with indirect references, this will only be the case + * when relocating a shared extent. In that case, root_objectid + * will be BTRFS_TREE_RELOC_OBJECTID. Otheriwse, parent must + * be 0 + * + * @root_objectid: The id of the root where this modification has originated, + * this can be either one of the well-known metadata trees or + * the subvolume id which references this extent. + * + * @owner: For data extents it is the inode number of the owning file. + * For metadata extents this parameter holds the level in the + * tree of the extent. + * + * @offset: For metadata extents the offset is ignored and is currently + * always passed as 0. For data extents it is the fileoffset + * this extent belongs to. + * + * @refs_to_add Number of references to add + * + * @extent_op Pointer to a structure, holding information necessary when + * updating a tree block's flags + * + */ +static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_node *node, + u64 parent, u64 root_objectid, + u64 owner, u64 offset, int refs_to_add, + struct btrfs_delayed_extent_op *extent_op) +{ + struct btrfs_path *path; + struct extent_buffer *leaf; + struct btrfs_extent_item *item; + struct btrfs_key key; + u64 bytenr = node->bytenr; + u64 num_bytes = node->num_bytes; + u64 refs; + int ret; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + path->leave_spinning = 1; + /* this will setup the path even if it fails to insert the back ref */ + ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes, + parent, root_objectid, owner, + offset, refs_to_add, extent_op); + if ((ret < 0 && ret != -EAGAIN) || !ret) + goto out; + + /* + * Ok we had -EAGAIN which means we didn't have space to insert and + * inline extent ref, so just update the reference count and add a + * normal backref. + */ + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); + refs = btrfs_extent_refs(leaf, item); + btrfs_set_extent_refs(leaf, item, refs + refs_to_add); + if (extent_op) + __run_delayed_extent_op(extent_op, leaf, item); + + btrfs_mark_buffer_dirty(leaf); + btrfs_release_path(path); + + path->leave_spinning = 1; + /* now insert the actual backref */ + if (owner < BTRFS_FIRST_FREE_OBJECTID) { + BUG_ON(refs_to_add != 1); + ret = insert_tree_block_ref(trans, path, bytenr, parent, + root_objectid); + } else { + ret = insert_extent_data_ref(trans, path, bytenr, parent, + root_objectid, owner, offset, + refs_to_add); + } + if (ret) + btrfs_abort_transaction(trans, ret); +out: + btrfs_free_path(path); + return ret; +} + +static int run_delayed_data_ref(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_node *node, + struct btrfs_delayed_extent_op *extent_op, + int insert_reserved) +{ + int ret = 0; + struct btrfs_delayed_data_ref *ref; + struct btrfs_key ins; + u64 parent = 0; + u64 ref_root = 0; + u64 flags = 0; + + ins.objectid = node->bytenr; + ins.offset = node->num_bytes; + ins.type = BTRFS_EXTENT_ITEM_KEY; + + ref = btrfs_delayed_node_to_data_ref(node); + trace_run_delayed_data_ref(trans->fs_info, node, ref, node->action); + + if (node->type == BTRFS_SHARED_DATA_REF_KEY) + parent = ref->parent; + ref_root = ref->root; + + if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) { + if (extent_op) + flags |= extent_op->flags_to_set; + ret = alloc_reserved_file_extent(trans, parent, ref_root, + flags, ref->objectid, + ref->offset, &ins, + node->ref_mod); + } else if (node->action == BTRFS_ADD_DELAYED_REF) { + ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root, + ref->objectid, ref->offset, + node->ref_mod, extent_op); + } else if (node->action == BTRFS_DROP_DELAYED_REF) { + ret = __btrfs_free_extent(trans, node, parent, + ref_root, ref->objectid, + ref->offset, node->ref_mod, + extent_op); + } else { + BUG(); + } + return ret; +} + +static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op, + struct extent_buffer *leaf, + struct btrfs_extent_item *ei) +{ + u64 flags = btrfs_extent_flags(leaf, ei); + if (extent_op->update_flags) { + flags |= extent_op->flags_to_set; + btrfs_set_extent_flags(leaf, ei, flags); + } + + if (extent_op->update_key) { + struct btrfs_tree_block_info *bi; + BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)); + bi = (struct btrfs_tree_block_info *)(ei + 1); + btrfs_set_tree_block_key(leaf, bi, &extent_op->key); + } +} + +static int run_delayed_extent_op(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_head *head, + struct btrfs_delayed_extent_op *extent_op) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_key key; + struct btrfs_path *path; + struct btrfs_extent_item *ei; + struct extent_buffer *leaf; + u32 item_size; + int ret; + int err = 0; + int metadata = !extent_op->is_data; + + if (TRANS_ABORTED(trans)) + return 0; + + if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) + metadata = 0; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + key.objectid = head->bytenr; + + if (metadata) { + key.type = BTRFS_METADATA_ITEM_KEY; + key.offset = extent_op->level; + } else { + key.type = BTRFS_EXTENT_ITEM_KEY; + key.offset = head->num_bytes; + } + +again: + path->leave_spinning = 1; + ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1); + if (ret < 0) { + err = ret; + goto out; + } + if (ret > 0) { + if (metadata) { + if (path->slots[0] > 0) { + path->slots[0]--; + btrfs_item_key_to_cpu(path->nodes[0], &key, + path->slots[0]); + if (key.objectid == head->bytenr && + key.type == BTRFS_EXTENT_ITEM_KEY && + key.offset == head->num_bytes) + ret = 0; + } + if (ret > 0) { + btrfs_release_path(path); + metadata = 0; + + key.objectid = head->bytenr; + key.offset = head->num_bytes; + key.type = BTRFS_EXTENT_ITEM_KEY; + goto again; + } + } else { + err = -EIO; + goto out; + } + } + + leaf = path->nodes[0]; + item_size = btrfs_item_size_nr(leaf, path->slots[0]); + + if (unlikely(item_size < sizeof(*ei))) { + err = -EINVAL; + btrfs_print_v0_err(fs_info); + btrfs_abort_transaction(trans, err); + goto out; + } + + ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); + __run_delayed_extent_op(extent_op, leaf, ei); + + btrfs_mark_buffer_dirty(leaf); +out: + btrfs_free_path(path); + return err; +} + +static int run_delayed_tree_ref(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_node *node, + struct btrfs_delayed_extent_op *extent_op, + int insert_reserved) +{ + int ret = 0; + struct btrfs_delayed_tree_ref *ref; + u64 parent = 0; + u64 ref_root = 0; + + ref = btrfs_delayed_node_to_tree_ref(node); + trace_run_delayed_tree_ref(trans->fs_info, node, ref, node->action); + + if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) + parent = ref->parent; + ref_root = ref->root; + + if (unlikely(node->ref_mod != 1)) { + btrfs_err(trans->fs_info, + "btree block %llu has %d references rather than 1: action %d ref_root %llu parent %llu", + node->bytenr, node->ref_mod, node->action, ref_root, + parent); + return -EUCLEAN; + } + if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) { + BUG_ON(!extent_op || !extent_op->update_flags); + ret = alloc_reserved_tree_block(trans, node, extent_op); + } else if (node->action == BTRFS_ADD_DELAYED_REF) { + ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root, + ref->level, 0, 1, extent_op); + } else if (node->action == BTRFS_DROP_DELAYED_REF) { + ret = __btrfs_free_extent(trans, node, parent, ref_root, + ref->level, 0, 1, extent_op); + } else { + BUG(); + } + return ret; +} + +/* helper function to actually process a single delayed ref entry */ +static int run_one_delayed_ref(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_node *node, + struct btrfs_delayed_extent_op *extent_op, + int insert_reserved) +{ + int ret = 0; + + if (TRANS_ABORTED(trans)) { + if (insert_reserved) + btrfs_pin_extent(trans, node->bytenr, node->num_bytes, 1); + return 0; + } + + if (node->type == BTRFS_TREE_BLOCK_REF_KEY || + node->type == BTRFS_SHARED_BLOCK_REF_KEY) + ret = run_delayed_tree_ref(trans, node, extent_op, + insert_reserved); + else if (node->type == BTRFS_EXTENT_DATA_REF_KEY || + node->type == BTRFS_SHARED_DATA_REF_KEY) + ret = run_delayed_data_ref(trans, node, extent_op, + insert_reserved); + else + BUG(); + if (ret && insert_reserved) + btrfs_pin_extent(trans, node->bytenr, node->num_bytes, 1); + if (ret < 0) + btrfs_err(trans->fs_info, +"failed to run delayed ref for logical %llu num_bytes %llu type %u action %u ref_mod %d: %d", + node->bytenr, node->num_bytes, node->type, + node->action, node->ref_mod, ret); + return ret; +} + +static inline struct btrfs_delayed_ref_node * +select_delayed_ref(struct btrfs_delayed_ref_head *head) +{ + struct btrfs_delayed_ref_node *ref; + + if (RB_EMPTY_ROOT(&head->ref_tree.rb_root)) + return NULL; + + /* + * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first. + * This is to prevent a ref count from going down to zero, which deletes + * the extent item from the extent tree, when there still are references + * to add, which would fail because they would not find the extent item. + */ + if (!list_empty(&head->ref_add_list)) + return list_first_entry(&head->ref_add_list, + struct btrfs_delayed_ref_node, add_list); + + ref = rb_entry(rb_first_cached(&head->ref_tree), + struct btrfs_delayed_ref_node, ref_node); + ASSERT(list_empty(&ref->add_list)); + return ref; +} + +static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, + struct btrfs_delayed_ref_head *head) +{ + spin_lock(&delayed_refs->lock); + head->processing = 0; + delayed_refs->num_heads_ready++; + spin_unlock(&delayed_refs->lock); + btrfs_delayed_ref_unlock(head); +} + +static struct btrfs_delayed_extent_op *cleanup_extent_op( + struct btrfs_delayed_ref_head *head) +{ + struct btrfs_delayed_extent_op *extent_op = head->extent_op; + + if (!extent_op) + return NULL; + + if (head->must_insert_reserved) { + head->extent_op = NULL; + btrfs_free_delayed_extent_op(extent_op); + return NULL; + } + return extent_op; +} + +static int run_and_cleanup_extent_op(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_head *head) +{ + struct btrfs_delayed_extent_op *extent_op; + int ret; + + extent_op = cleanup_extent_op(head); + if (!extent_op) + return 0; + head->extent_op = NULL; + spin_unlock(&head->lock); + ret = run_delayed_extent_op(trans, head, extent_op); + btrfs_free_delayed_extent_op(extent_op); + return ret ? ret : 1; +} + +void btrfs_cleanup_ref_head_accounting(struct btrfs_fs_info *fs_info, + struct btrfs_delayed_ref_root *delayed_refs, + struct btrfs_delayed_ref_head *head) +{ + int nr_items = 1; /* Dropping this ref head update. */ + + /* + * We had csum deletions accounted for in our delayed refs rsv, we need + * to drop the csum leaves for this update from our delayed_refs_rsv. + */ + if (head->total_ref_mod < 0 && head->is_data) { + spin_lock(&delayed_refs->lock); + delayed_refs->pending_csums -= head->num_bytes; + spin_unlock(&delayed_refs->lock); + nr_items += btrfs_csum_bytes_to_leaves(fs_info, head->num_bytes); + } + + /* + * We were dropping refs, or had a new ref and dropped it, and thus must + * adjust down our total_bytes_pinned, the space may or may not have + * been pinned and so is accounted for properly in the pinned space by + * now. + */ + if (head->total_ref_mod < 0 || + (head->total_ref_mod == 0 && head->must_insert_reserved)) { + u64 flags = btrfs_ref_head_to_space_flags(head); + + btrfs_mod_total_bytes_pinned(fs_info, flags, -head->num_bytes); + } + + btrfs_delayed_refs_rsv_release(fs_info, nr_items); +} + +static int cleanup_ref_head(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_head *head) +{ + + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_delayed_ref_root *delayed_refs; + int ret; + + delayed_refs = &trans->transaction->delayed_refs; + + ret = run_and_cleanup_extent_op(trans, head); + if (ret < 0) { + unselect_delayed_ref_head(delayed_refs, head); + btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret); + return ret; + } else if (ret) { + return ret; + } + + /* + * Need to drop our head ref lock and re-acquire the delayed ref lock + * and then re-check to make sure nobody got added. + */ + spin_unlock(&head->lock); + spin_lock(&delayed_refs->lock); + spin_lock(&head->lock); + if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root) || head->extent_op) { + spin_unlock(&head->lock); + spin_unlock(&delayed_refs->lock); + return 1; + } + btrfs_delete_ref_head(delayed_refs, head); + spin_unlock(&head->lock); + spin_unlock(&delayed_refs->lock); + + if (head->must_insert_reserved) { + btrfs_pin_extent(trans, head->bytenr, head->num_bytes, 1); + if (head->is_data) { + ret = btrfs_del_csums(trans, fs_info->csum_root, + head->bytenr, head->num_bytes); + } + } + + btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head); + + trace_run_delayed_ref_head(fs_info, head, 0); + btrfs_delayed_ref_unlock(head); + btrfs_put_delayed_ref_head(head); + return ret; +} + +static struct btrfs_delayed_ref_head *btrfs_obtain_ref_head( + struct btrfs_trans_handle *trans) +{ + struct btrfs_delayed_ref_root *delayed_refs = + &trans->transaction->delayed_refs; + struct btrfs_delayed_ref_head *head = NULL; + int ret; + + spin_lock(&delayed_refs->lock); + head = btrfs_select_ref_head(delayed_refs); + if (!head) { + spin_unlock(&delayed_refs->lock); + return head; + } + + /* + * Grab the lock that says we are going to process all the refs for + * this head + */ + ret = btrfs_delayed_ref_lock(delayed_refs, head); + spin_unlock(&delayed_refs->lock); + + /* + * We may have dropped the spin lock to get the head mutex lock, and + * that might have given someone else time to free the head. If that's + * true, it has been removed from our list and we can move on. + */ + if (ret == -EAGAIN) + head = ERR_PTR(-EAGAIN); + + return head; +} + +static int btrfs_run_delayed_refs_for_head(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_head *locked_ref, + unsigned long *run_refs) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_delayed_ref_root *delayed_refs; + struct btrfs_delayed_extent_op *extent_op; + struct btrfs_delayed_ref_node *ref; + int must_insert_reserved = 0; + int ret; + + delayed_refs = &trans->transaction->delayed_refs; + + lockdep_assert_held(&locked_ref->mutex); + lockdep_assert_held(&locked_ref->lock); + + while ((ref = select_delayed_ref(locked_ref))) { + if (ref->seq && + btrfs_check_delayed_seq(fs_info, ref->seq)) { + spin_unlock(&locked_ref->lock); + unselect_delayed_ref_head(delayed_refs, locked_ref); + return -EAGAIN; + } + + (*run_refs)++; + ref->in_tree = 0; + rb_erase_cached(&ref->ref_node, &locked_ref->ref_tree); + RB_CLEAR_NODE(&ref->ref_node); + if (!list_empty(&ref->add_list)) + list_del(&ref->add_list); + /* + * When we play the delayed ref, also correct the ref_mod on + * head + */ + switch (ref->action) { + case BTRFS_ADD_DELAYED_REF: + case BTRFS_ADD_DELAYED_EXTENT: + locked_ref->ref_mod -= ref->ref_mod; + break; + case BTRFS_DROP_DELAYED_REF: + locked_ref->ref_mod += ref->ref_mod; + break; + default: + WARN_ON(1); + } + atomic_dec(&delayed_refs->num_entries); + + /* + * Record the must_insert_reserved flag before we drop the + * spin lock. + */ + must_insert_reserved = locked_ref->must_insert_reserved; + locked_ref->must_insert_reserved = 0; + + extent_op = locked_ref->extent_op; + locked_ref->extent_op = NULL; + spin_unlock(&locked_ref->lock); + + ret = run_one_delayed_ref(trans, ref, extent_op, + must_insert_reserved); + + btrfs_free_delayed_extent_op(extent_op); + if (ret) { + unselect_delayed_ref_head(delayed_refs, locked_ref); + btrfs_put_delayed_ref(ref); + return ret; + } + + btrfs_put_delayed_ref(ref); + cond_resched(); + + spin_lock(&locked_ref->lock); + btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref); + } + + return 0; +} + +/* + * Returns 0 on success or if called with an already aborted transaction. + * Returns -ENOMEM or -EIO on failure and will abort the transaction. + */ +static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, + unsigned long nr) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_delayed_ref_root *delayed_refs; + struct btrfs_delayed_ref_head *locked_ref = NULL; + ktime_t start = ktime_get(); + int ret; + unsigned long count = 0; + unsigned long actual_count = 0; + + delayed_refs = &trans->transaction->delayed_refs; + do { + if (!locked_ref) { + locked_ref = btrfs_obtain_ref_head(trans); + if (IS_ERR_OR_NULL(locked_ref)) { + if (PTR_ERR(locked_ref) == -EAGAIN) { + continue; + } else { + break; + } + } + count++; + } + /* + * We need to try and merge add/drops of the same ref since we + * can run into issues with relocate dropping the implicit ref + * and then it being added back again before the drop can + * finish. If we merged anything we need to re-loop so we can + * get a good ref. + * Or we can get node references of the same type that weren't + * merged when created due to bumps in the tree mod seq, and + * we need to merge them to prevent adding an inline extent + * backref before dropping it (triggering a BUG_ON at + * insert_inline_extent_backref()). + */ + spin_lock(&locked_ref->lock); + btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref); + + ret = btrfs_run_delayed_refs_for_head(trans, locked_ref, + &actual_count); + if (ret < 0 && ret != -EAGAIN) { + /* + * Error, btrfs_run_delayed_refs_for_head already + * unlocked everything so just bail out + */ + return ret; + } else if (!ret) { + /* + * Success, perform the usual cleanup of a processed + * head + */ + ret = cleanup_ref_head(trans, locked_ref); + if (ret > 0 ) { + /* We dropped our lock, we need to loop. */ + ret = 0; + continue; + } else if (ret) { + return ret; + } + } + + /* + * Either success case or btrfs_run_delayed_refs_for_head + * returned -EAGAIN, meaning we need to select another head + */ + + locked_ref = NULL; + cond_resched(); + } while ((nr != -1 && count < nr) || locked_ref); + + /* + * We don't want to include ref heads since we can have empty ref heads + * and those will drastically skew our runtime down since we just do + * accounting, no actual extent tree updates. + */ + if (actual_count > 0) { + u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start)); + u64 avg; + + /* + * We weigh the current average higher than our current runtime + * to avoid large swings in the average. + */ + spin_lock(&delayed_refs->lock); + avg = fs_info->avg_delayed_ref_runtime * 3 + runtime; + fs_info->avg_delayed_ref_runtime = avg >> 2; /* div by 4 */ + spin_unlock(&delayed_refs->lock); + } + return 0; +} + +#ifdef SCRAMBLE_DELAYED_REFS +/* + * Normally delayed refs get processed in ascending bytenr order. This + * correlates in most cases to the order added. To expose dependencies on this + * order, we start to process the tree in the middle instead of the beginning + */ +static u64 find_middle(struct rb_root *root) +{ + struct rb_node *n = root->rb_node; + struct btrfs_delayed_ref_node *entry; + int alt = 1; + u64 middle; + u64 first = 0, last = 0; + + n = rb_first(root); + if (n) { + entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node); + first = entry->bytenr; + } + n = rb_last(root); + if (n) { + entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node); + last = entry->bytenr; + } + n = root->rb_node; + + while (n) { + entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node); + WARN_ON(!entry->in_tree); + + middle = entry->bytenr; + + if (alt) + n = n->rb_left; + else + n = n->rb_right; + + alt = 1 - alt; + } + return middle; +} +#endif + +/* + * Takes the number of bytes to be csumm'ed and figures out how many leaves it + * would require to store the csums for that many bytes. + */ +u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes) +{ + u64 csum_size; + u64 num_csums_per_leaf; + u64 num_csums; + + csum_size = BTRFS_MAX_ITEM_SIZE(fs_info); + num_csums_per_leaf = div64_u64(csum_size, + (u64)btrfs_super_csum_size(fs_info->super_copy)); + num_csums = div64_u64(csum_bytes, fs_info->sectorsize); + num_csums += num_csums_per_leaf - 1; + num_csums = div64_u64(num_csums, num_csums_per_leaf); + return num_csums; +} + +/* + * this starts processing the delayed reference count updates and + * extent insertions we have queued up so far. count can be + * 0, which means to process everything in the tree at the start + * of the run (but not newly added entries), or it can be some target + * number you'd like to process. + * + * Returns 0 on success or if called with an aborted transaction + * Returns <0 on error and aborts the transaction + */ +int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, + unsigned long count) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct rb_node *node; + struct btrfs_delayed_ref_root *delayed_refs; + struct btrfs_delayed_ref_head *head; + int ret; + int run_all = count == (unsigned long)-1; + + /* We'll clean this up in btrfs_cleanup_transaction */ + if (TRANS_ABORTED(trans)) + return 0; + + if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags)) + return 0; + + delayed_refs = &trans->transaction->delayed_refs; + if (count == 0) + count = atomic_read(&delayed_refs->num_entries) * 2; + +again: +#ifdef SCRAMBLE_DELAYED_REFS + delayed_refs->run_delayed_start = find_middle(&delayed_refs->root); +#endif + ret = __btrfs_run_delayed_refs(trans, count); + if (ret < 0) { + btrfs_abort_transaction(trans, ret); + return ret; + } + + if (run_all) { + btrfs_create_pending_block_groups(trans); + + spin_lock(&delayed_refs->lock); + node = rb_first_cached(&delayed_refs->href_root); + if (!node) { + spin_unlock(&delayed_refs->lock); + goto out; + } + head = rb_entry(node, struct btrfs_delayed_ref_head, + href_node); + refcount_inc(&head->refs); + spin_unlock(&delayed_refs->lock); + + /* Mutex was contended, block until it's released and retry. */ + mutex_lock(&head->mutex); + mutex_unlock(&head->mutex); + + btrfs_put_delayed_ref_head(head); + cond_resched(); + goto again; + } +out: + return 0; +} + +int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans, + struct extent_buffer *eb, u64 flags, + int level, int is_data) +{ + struct btrfs_delayed_extent_op *extent_op; + int ret; + + extent_op = btrfs_alloc_delayed_extent_op(); + if (!extent_op) + return -ENOMEM; + + extent_op->flags_to_set = flags; + extent_op->update_flags = true; + extent_op->update_key = false; + extent_op->is_data = is_data ? true : false; + extent_op->level = level; + + ret = btrfs_add_delayed_extent_op(trans, eb->start, eb->len, extent_op); + if (ret) + btrfs_free_delayed_extent_op(extent_op); + return ret; +} + +static noinline int check_delayed_ref(struct btrfs_root *root, + struct btrfs_path *path, + u64 objectid, u64 offset, u64 bytenr) +{ + struct btrfs_delayed_ref_head *head; + struct btrfs_delayed_ref_node *ref; + struct btrfs_delayed_data_ref *data_ref; + struct btrfs_delayed_ref_root *delayed_refs; + struct btrfs_transaction *cur_trans; + struct rb_node *node; + int ret = 0; + + spin_lock(&root->fs_info->trans_lock); + cur_trans = root->fs_info->running_transaction; + if (cur_trans) + refcount_inc(&cur_trans->use_count); + spin_unlock(&root->fs_info->trans_lock); + if (!cur_trans) + return 0; + + delayed_refs = &cur_trans->delayed_refs; + spin_lock(&delayed_refs->lock); + head = btrfs_find_delayed_ref_head(delayed_refs, bytenr); + if (!head) { + spin_unlock(&delayed_refs->lock); + btrfs_put_transaction(cur_trans); + return 0; + } + + if (!mutex_trylock(&head->mutex)) { + refcount_inc(&head->refs); + spin_unlock(&delayed_refs->lock); + + btrfs_release_path(path); + + /* + * Mutex was contended, block until it's released and let + * caller try again + */ + mutex_lock(&head->mutex); + mutex_unlock(&head->mutex); + btrfs_put_delayed_ref_head(head); + btrfs_put_transaction(cur_trans); + return -EAGAIN; + } + spin_unlock(&delayed_refs->lock); + + spin_lock(&head->lock); + /* + * XXX: We should replace this with a proper search function in the + * future. + */ + for (node = rb_first_cached(&head->ref_tree); node; + node = rb_next(node)) { + ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node); + /* If it's a shared ref we know a cross reference exists */ + if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) { + ret = 1; + break; + } + + data_ref = btrfs_delayed_node_to_data_ref(ref); + + /* + * If our ref doesn't match the one we're currently looking at + * then we have a cross reference. + */ + if (data_ref->root != root->root_key.objectid || + data_ref->objectid != objectid || + data_ref->offset != offset) { + ret = 1; + break; + } + } + spin_unlock(&head->lock); + mutex_unlock(&head->mutex); + btrfs_put_transaction(cur_trans); + return ret; +} + +static noinline int check_committed_ref(struct btrfs_root *root, + struct btrfs_path *path, + u64 objectid, u64 offset, u64 bytenr, + bool strict) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_root *extent_root = fs_info->extent_root; + struct extent_buffer *leaf; + struct btrfs_extent_data_ref *ref; + struct btrfs_extent_inline_ref *iref; + struct btrfs_extent_item *ei; + struct btrfs_key key; + u32 item_size; + int type; + int ret; + + key.objectid = bytenr; + key.offset = (u64)-1; + key.type = BTRFS_EXTENT_ITEM_KEY; + + ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0); + if (ret < 0) + goto out; + BUG_ON(ret == 0); /* Corruption */ + + ret = -ENOENT; + if (path->slots[0] == 0) + goto out; + + path->slots[0]--; + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + + if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY) + goto out; + + ret = 1; + item_size = btrfs_item_size_nr(leaf, path->slots[0]); + ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); + + /* If extent item has more than 1 inline ref then it's shared */ + if (item_size != sizeof(*ei) + + btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY)) + goto out; + + /* + * If extent created before last snapshot => it's shared unless the + * snapshot has been deleted. Use the heuristic if strict is false. + */ + if (!strict && + (btrfs_extent_generation(leaf, ei) <= + btrfs_root_last_snapshot(&root->root_item))) + goto out; + + iref = (struct btrfs_extent_inline_ref *)(ei + 1); + + /* If this extent has SHARED_DATA_REF then it's shared */ + type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA); + if (type != BTRFS_EXTENT_DATA_REF_KEY) + goto out; + + ref = (struct btrfs_extent_data_ref *)(&iref->offset); + if (btrfs_extent_refs(leaf, ei) != + btrfs_extent_data_ref_count(leaf, ref) || + btrfs_extent_data_ref_root(leaf, ref) != + root->root_key.objectid || + btrfs_extent_data_ref_objectid(leaf, ref) != objectid || + btrfs_extent_data_ref_offset(leaf, ref) != offset) + goto out; + + ret = 0; +out: + return ret; +} + +int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset, + u64 bytenr, bool strict) +{ + struct btrfs_path *path; + int ret; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + do { + ret = check_committed_ref(root, path, objectid, + offset, bytenr, strict); + if (ret && ret != -ENOENT) + goto out; + + ret = check_delayed_ref(root, path, objectid, offset, bytenr); + } while (ret == -EAGAIN); + +out: + btrfs_free_path(path); + if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID) + WARN_ON(ret > 0); + return ret; +} + +static int __btrfs_mod_ref(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct extent_buffer *buf, + int full_backref, int inc) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + u64 bytenr; + u64 num_bytes; + u64 parent; + u64 ref_root; + u32 nritems; + struct btrfs_key key; + struct btrfs_file_extent_item *fi; + struct btrfs_ref generic_ref = { 0 }; + bool for_reloc = btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC); + int i; + int action; + int level; + int ret = 0; + + if (btrfs_is_testing(fs_info)) + return 0; + + ref_root = btrfs_header_owner(buf); + nritems = btrfs_header_nritems(buf); + level = btrfs_header_level(buf); + + if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && level == 0) + return 0; + + if (full_backref) + parent = buf->start; + else + parent = 0; + if (inc) + action = BTRFS_ADD_DELAYED_REF; + else + action = BTRFS_DROP_DELAYED_REF; + + for (i = 0; i < nritems; i++) { + if (level == 0) { + btrfs_item_key_to_cpu(buf, &key, i); + if (key.type != BTRFS_EXTENT_DATA_KEY) + continue; + fi = btrfs_item_ptr(buf, i, + struct btrfs_file_extent_item); + if (btrfs_file_extent_type(buf, fi) == + BTRFS_FILE_EXTENT_INLINE) + continue; + bytenr = btrfs_file_extent_disk_bytenr(buf, fi); + if (bytenr == 0) + continue; + + num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi); + key.offset -= btrfs_file_extent_offset(buf, fi); + btrfs_init_generic_ref(&generic_ref, action, bytenr, + num_bytes, parent); + generic_ref.real_root = root->root_key.objectid; + btrfs_init_data_ref(&generic_ref, ref_root, key.objectid, + key.offset); + generic_ref.skip_qgroup = for_reloc; + if (inc) + ret = btrfs_inc_extent_ref(trans, &generic_ref); + else + ret = btrfs_free_extent(trans, &generic_ref); + if (ret) + goto fail; + } else { + bytenr = btrfs_node_blockptr(buf, i); + num_bytes = fs_info->nodesize; + btrfs_init_generic_ref(&generic_ref, action, bytenr, + num_bytes, parent); + generic_ref.real_root = root->root_key.objectid; + btrfs_init_tree_ref(&generic_ref, level - 1, ref_root); + generic_ref.skip_qgroup = for_reloc; + if (inc) + ret = btrfs_inc_extent_ref(trans, &generic_ref); + else + ret = btrfs_free_extent(trans, &generic_ref); + if (ret) + goto fail; + } + } + return 0; +fail: + return ret; +} + +int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, + struct extent_buffer *buf, int full_backref) +{ + return __btrfs_mod_ref(trans, root, buf, full_backref, 1); +} + +int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, + struct extent_buffer *buf, int full_backref) +{ + return __btrfs_mod_ref(trans, root, buf, full_backref, 0); +} + +int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr) +{ + struct btrfs_block_group *block_group; + int readonly = 0; + + block_group = btrfs_lookup_block_group(fs_info, bytenr); + if (!block_group || block_group->ro) + readonly = 1; + if (block_group) + btrfs_put_block_group(block_group); + return readonly; +} + +static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + u64 flags; + u64 ret; + + if (data) + flags = BTRFS_BLOCK_GROUP_DATA; + else if (root == fs_info->chunk_root) + flags = BTRFS_BLOCK_GROUP_SYSTEM; + else + flags = BTRFS_BLOCK_GROUP_METADATA; + + ret = btrfs_get_alloc_profile(fs_info, flags); + return ret; +} + +static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start) +{ + struct btrfs_block_group *cache; + u64 bytenr; + + spin_lock(&fs_info->block_group_cache_lock); + bytenr = fs_info->first_logical_byte; + spin_unlock(&fs_info->block_group_cache_lock); + + if (bytenr < (u64)-1) + return bytenr; + + cache = btrfs_lookup_first_block_group(fs_info, search_start); + if (!cache) + return 0; + + bytenr = cache->start; + btrfs_put_block_group(cache); + + return bytenr; +} + +static int pin_down_extent(struct btrfs_trans_handle *trans, + struct btrfs_block_group *cache, + u64 bytenr, u64 num_bytes, int reserved) +{ + struct btrfs_fs_info *fs_info = cache->fs_info; + + spin_lock(&cache->space_info->lock); + spin_lock(&cache->lock); + cache->pinned += num_bytes; + btrfs_space_info_update_bytes_pinned(fs_info, cache->space_info, + num_bytes); + if (reserved) { + cache->reserved -= num_bytes; + cache->space_info->bytes_reserved -= num_bytes; + } + spin_unlock(&cache->lock); + spin_unlock(&cache->space_info->lock); + + __btrfs_mod_total_bytes_pinned(cache->space_info, num_bytes); + set_extent_dirty(&trans->transaction->pinned_extents, bytenr, + bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL); + return 0; +} + +int btrfs_pin_extent(struct btrfs_trans_handle *trans, + u64 bytenr, u64 num_bytes, int reserved) +{ + struct btrfs_block_group *cache; + + cache = btrfs_lookup_block_group(trans->fs_info, bytenr); + BUG_ON(!cache); /* Logic error */ + + pin_down_extent(trans, cache, bytenr, num_bytes, reserved); + + btrfs_put_block_group(cache); + return 0; +} + +/* + * this function must be called within transaction + */ +int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans, + u64 bytenr, u64 num_bytes) +{ + struct btrfs_block_group *cache; + int ret; + + btrfs_add_excluded_extent(trans->fs_info, bytenr, num_bytes); + + cache = btrfs_lookup_block_group(trans->fs_info, bytenr); + if (!cache) + return -EINVAL; + + /* + * pull in the free space cache (if any) so that our pin + * removes the free space from the cache. We have load_only set + * to one because the slow code to read in the free extents does check + * the pinned extents. + */ + btrfs_cache_block_group(cache, 1); + + pin_down_extent(trans, cache, bytenr, num_bytes, 0); + + /* remove us from the free space cache (if we're there at all) */ + ret = btrfs_remove_free_space(cache, bytenr, num_bytes); + btrfs_put_block_group(cache); + return ret; +} + +static int __exclude_logged_extent(struct btrfs_fs_info *fs_info, + u64 start, u64 num_bytes) +{ + int ret; + struct btrfs_block_group *block_group; + struct btrfs_caching_control *caching_ctl; + + block_group = btrfs_lookup_block_group(fs_info, start); + if (!block_group) + return -EINVAL; + + btrfs_cache_block_group(block_group, 0); + caching_ctl = btrfs_get_caching_control(block_group); + + if (!caching_ctl) { + /* Logic error */ + BUG_ON(!btrfs_block_group_done(block_group)); + ret = btrfs_remove_free_space(block_group, start, num_bytes); + } else { + mutex_lock(&caching_ctl->mutex); + + if (start >= caching_ctl->progress) { + ret = btrfs_add_excluded_extent(fs_info, start, + num_bytes); + } else if (start + num_bytes <= caching_ctl->progress) { + ret = btrfs_remove_free_space(block_group, + start, num_bytes); + } else { + num_bytes = caching_ctl->progress - start; + ret = btrfs_remove_free_space(block_group, + start, num_bytes); + if (ret) + goto out_lock; + + num_bytes = (start + num_bytes) - + caching_ctl->progress; + start = caching_ctl->progress; + ret = btrfs_add_excluded_extent(fs_info, start, + num_bytes); + } +out_lock: + mutex_unlock(&caching_ctl->mutex); + btrfs_put_caching_control(caching_ctl); + } + btrfs_put_block_group(block_group); + return ret; +} + +int btrfs_exclude_logged_extents(struct extent_buffer *eb) +{ + struct btrfs_fs_info *fs_info = eb->fs_info; + struct btrfs_file_extent_item *item; + struct btrfs_key key; + int found_type; + int i; + int ret = 0; + + if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) + return 0; + + for (i = 0; i < btrfs_header_nritems(eb); i++) { + btrfs_item_key_to_cpu(eb, &key, i); + if (key.type != BTRFS_EXTENT_DATA_KEY) + continue; + item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item); + found_type = btrfs_file_extent_type(eb, item); + if (found_type == BTRFS_FILE_EXTENT_INLINE) + continue; + if (btrfs_file_extent_disk_bytenr(eb, item) == 0) + continue; + key.objectid = btrfs_file_extent_disk_bytenr(eb, item); + key.offset = btrfs_file_extent_disk_num_bytes(eb, item); + ret = __exclude_logged_extent(fs_info, key.objectid, key.offset); + if (ret) + break; + } + + return ret; +} + +static void +btrfs_inc_block_group_reservations(struct btrfs_block_group *bg) +{ + atomic_inc(&bg->reservations); +} + +/* + * Returns the free cluster for the given space info and sets empty_cluster to + * what it should be based on the mount options. + */ +static struct btrfs_free_cluster * +fetch_cluster_info(struct btrfs_fs_info *fs_info, + struct btrfs_space_info *space_info, u64 *empty_cluster) +{ + struct btrfs_free_cluster *ret = NULL; + + *empty_cluster = 0; + if (btrfs_mixed_space_info(space_info)) + return ret; + + if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) { + ret = &fs_info->meta_alloc_cluster; + if (btrfs_test_opt(fs_info, SSD)) + *empty_cluster = SZ_2M; + else + *empty_cluster = SZ_64K; + } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) && + btrfs_test_opt(fs_info, SSD_SPREAD)) { + *empty_cluster = SZ_2M; + ret = &fs_info->data_alloc_cluster; + } + + return ret; +} + +static int unpin_extent_range(struct btrfs_fs_info *fs_info, + u64 start, u64 end, + const bool return_free_space) +{ + struct btrfs_block_group *cache = NULL; + struct btrfs_space_info *space_info; + struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv; + struct btrfs_free_cluster *cluster = NULL; + u64 len; + u64 total_unpinned = 0; + u64 empty_cluster = 0; + bool readonly; + + while (start <= end) { + readonly = false; + if (!cache || + start >= cache->start + cache->length) { + if (cache) + btrfs_put_block_group(cache); + total_unpinned = 0; + cache = btrfs_lookup_block_group(fs_info, start); + BUG_ON(!cache); /* Logic error */ + + cluster = fetch_cluster_info(fs_info, + cache->space_info, + &empty_cluster); + empty_cluster <<= 1; + } + + len = cache->start + cache->length - start; + len = min(len, end + 1 - start); + + if (start < cache->last_byte_to_unpin && return_free_space) { + u64 add_len = min(len, cache->last_byte_to_unpin - start); + + btrfs_add_free_space(cache, start, add_len); + } + + start += len; + total_unpinned += len; + space_info = cache->space_info; + + /* + * If this space cluster has been marked as fragmented and we've + * unpinned enough in this block group to potentially allow a + * cluster to be created inside of it go ahead and clear the + * fragmented check. + */ + if (cluster && cluster->fragmented && + total_unpinned > empty_cluster) { + spin_lock(&cluster->lock); + cluster->fragmented = 0; + spin_unlock(&cluster->lock); + } + + spin_lock(&space_info->lock); + spin_lock(&cache->lock); + cache->pinned -= len; + btrfs_space_info_update_bytes_pinned(fs_info, space_info, -len); + space_info->max_extent_size = 0; + __btrfs_mod_total_bytes_pinned(space_info, -len); + if (cache->ro) { + space_info->bytes_readonly += len; + readonly = true; + } + spin_unlock(&cache->lock); + if (!readonly && return_free_space && + global_rsv->space_info == space_info) { + u64 to_add = len; + + spin_lock(&global_rsv->lock); + if (!global_rsv->full) { + to_add = min(len, global_rsv->size - + global_rsv->reserved); + global_rsv->reserved += to_add; + btrfs_space_info_update_bytes_may_use(fs_info, + space_info, to_add); + if (global_rsv->reserved >= global_rsv->size) + global_rsv->full = 1; + len -= to_add; + } + spin_unlock(&global_rsv->lock); + } + /* Add to any tickets we may have */ + if (!readonly && return_free_space && len) + btrfs_try_granting_tickets(fs_info, space_info); + spin_unlock(&space_info->lock); + } + + if (cache) + btrfs_put_block_group(cache); + return 0; +} + +int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_block_group *block_group, *tmp; + struct list_head *deleted_bgs; + struct extent_io_tree *unpin; + u64 start; + u64 end; + int ret; + + unpin = &trans->transaction->pinned_extents; + + while (!TRANS_ABORTED(trans)) { + struct extent_state *cached_state = NULL; + + mutex_lock(&fs_info->unused_bg_unpin_mutex); + ret = find_first_extent_bit(unpin, 0, &start, &end, + EXTENT_DIRTY, &cached_state); + if (ret) { + mutex_unlock(&fs_info->unused_bg_unpin_mutex); + break; + } + if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) + clear_extent_bits(&fs_info->excluded_extents, start, + end, EXTENT_UPTODATE); + + if (btrfs_test_opt(fs_info, DISCARD_SYNC)) + ret = btrfs_discard_extent(fs_info, start, + end + 1 - start, NULL); + + clear_extent_dirty(unpin, start, end, &cached_state); + unpin_extent_range(fs_info, start, end, true); + mutex_unlock(&fs_info->unused_bg_unpin_mutex); + free_extent_state(cached_state); + cond_resched(); + } + + if (btrfs_test_opt(fs_info, DISCARD_ASYNC)) { + btrfs_discard_calc_delay(&fs_info->discard_ctl); + btrfs_discard_schedule_work(&fs_info->discard_ctl, true); + } + + /* + * Transaction is finished. We don't need the lock anymore. We + * do need to clean up the block groups in case of a transaction + * abort. + */ + deleted_bgs = &trans->transaction->deleted_bgs; + list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) { + u64 trimmed = 0; + + ret = -EROFS; + if (!TRANS_ABORTED(trans)) + ret = btrfs_discard_extent(fs_info, + block_group->start, + block_group->length, + &trimmed); + + list_del_init(&block_group->bg_list); + btrfs_unfreeze_block_group(block_group); + btrfs_put_block_group(block_group); + + if (ret) { + const char *errstr = btrfs_decode_error(ret); + btrfs_warn(fs_info, + "discard failed while removing blockgroup: errno=%d %s", + ret, errstr); + } + } + + return 0; +} + +/* + * Drop one or more refs of @node. + * + * 1. Locate the extent refs. + * It's either inline in EXTENT/METADATA_ITEM or in keyed SHARED_* item. + * Locate it, then reduce the refs number or remove the ref line completely. + * + * 2. Update the refs count in EXTENT/METADATA_ITEM + * + * Inline backref case: + * + * in extent tree we have: + * + * item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 16201 itemsize 82 + * refs 2 gen 6 flags DATA + * extent data backref root FS_TREE objectid 258 offset 0 count 1 + * extent data backref root FS_TREE objectid 257 offset 0 count 1 + * + * This function gets called with: + * + * node->bytenr = 13631488 + * node->num_bytes = 1048576 + * root_objectid = FS_TREE + * owner_objectid = 257 + * owner_offset = 0 + * refs_to_drop = 1 + * + * Then we should get some like: + * + * item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 16201 itemsize 82 + * refs 1 gen 6 flags DATA + * extent data backref root FS_TREE objectid 258 offset 0 count 1 + * + * Keyed backref case: + * + * in extent tree we have: + * + * item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 3971 itemsize 24 + * refs 754 gen 6 flags DATA + * [...] + * item 2 key (13631488 EXTENT_DATA_REF <HASH>) itemoff 3915 itemsize 28 + * extent data backref root FS_TREE objectid 866 offset 0 count 1 + * + * This function get called with: + * + * node->bytenr = 13631488 + * node->num_bytes = 1048576 + * root_objectid = FS_TREE + * owner_objectid = 866 + * owner_offset = 0 + * refs_to_drop = 1 + * + * Then we should get some like: + * + * item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 3971 itemsize 24 + * refs 753 gen 6 flags DATA + * + * And that (13631488 EXTENT_DATA_REF <HASH>) gets removed. + */ +static int __btrfs_free_extent(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_node *node, u64 parent, + u64 root_objectid, u64 owner_objectid, + u64 owner_offset, int refs_to_drop, + struct btrfs_delayed_extent_op *extent_op) +{ + struct btrfs_fs_info *info = trans->fs_info; + struct btrfs_key key; + struct btrfs_path *path; + struct btrfs_root *extent_root = info->extent_root; + struct extent_buffer *leaf; + struct btrfs_extent_item *ei; + struct btrfs_extent_inline_ref *iref; + int ret; + int is_data; + int extent_slot = 0; + int found_extent = 0; + int num_to_del = 1; + u32 item_size; + u64 refs; + u64 bytenr = node->bytenr; + u64 num_bytes = node->num_bytes; + int last_ref = 0; + bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA); + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + path->leave_spinning = 1; + + is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID; + + if (!is_data && refs_to_drop != 1) { + btrfs_crit(info, +"invalid refs_to_drop, dropping more than 1 refs for tree block %llu refs_to_drop %u", + node->bytenr, refs_to_drop); + ret = -EINVAL; + btrfs_abort_transaction(trans, ret); + goto out; + } + + if (is_data) + skinny_metadata = false; + + ret = lookup_extent_backref(trans, path, &iref, bytenr, num_bytes, + parent, root_objectid, owner_objectid, + owner_offset); + if (ret == 0) { + /* + * Either the inline backref or the SHARED_DATA_REF/ + * SHARED_BLOCK_REF is found + * + * Here is a quick path to locate EXTENT/METADATA_ITEM. + * It's possible the EXTENT/METADATA_ITEM is near current slot. + */ + extent_slot = path->slots[0]; + while (extent_slot >= 0) { + btrfs_item_key_to_cpu(path->nodes[0], &key, + extent_slot); + if (key.objectid != bytenr) + break; + if (key.type == BTRFS_EXTENT_ITEM_KEY && + key.offset == num_bytes) { + found_extent = 1; + break; + } + if (key.type == BTRFS_METADATA_ITEM_KEY && + key.offset == owner_objectid) { + found_extent = 1; + break; + } + + /* Quick path didn't find the EXTEMT/METADATA_ITEM */ + if (path->slots[0] - extent_slot > 5) + break; + extent_slot--; + } + + if (!found_extent) { + if (iref) { + btrfs_crit(info, +"invalid iref, no EXTENT/METADATA_ITEM found but has inline extent ref"); + btrfs_abort_transaction(trans, -EUCLEAN); + goto err_dump; + } + /* Must be SHARED_* item, remove the backref first */ + ret = remove_extent_backref(trans, path, NULL, + refs_to_drop, + is_data, &last_ref); + if (ret) { + btrfs_abort_transaction(trans, ret); + goto out; + } + btrfs_release_path(path); + path->leave_spinning = 1; + + /* Slow path to locate EXTENT/METADATA_ITEM */ + key.objectid = bytenr; + key.type = BTRFS_EXTENT_ITEM_KEY; + key.offset = num_bytes; + + if (!is_data && skinny_metadata) { + key.type = BTRFS_METADATA_ITEM_KEY; + key.offset = owner_objectid; + } + + ret = btrfs_search_slot(trans, extent_root, + &key, path, -1, 1); + if (ret > 0 && skinny_metadata && path->slots[0]) { + /* + * Couldn't find our skinny metadata item, + * see if we have ye olde extent item. + */ + path->slots[0]--; + btrfs_item_key_to_cpu(path->nodes[0], &key, + path->slots[0]); + if (key.objectid == bytenr && + key.type == BTRFS_EXTENT_ITEM_KEY && + key.offset == num_bytes) + ret = 0; + } + + if (ret > 0 && skinny_metadata) { + skinny_metadata = false; + key.objectid = bytenr; + key.type = BTRFS_EXTENT_ITEM_KEY; + key.offset = num_bytes; + btrfs_release_path(path); + ret = btrfs_search_slot(trans, extent_root, + &key, path, -1, 1); + } + + if (ret) { + btrfs_err(info, + "umm, got %d back from search, was looking for %llu", + ret, bytenr); + if (ret > 0) + btrfs_print_leaf(path->nodes[0]); + } + if (ret < 0) { + btrfs_abort_transaction(trans, ret); + goto out; + } + extent_slot = path->slots[0]; + } + } else if (WARN_ON(ret == -ENOENT)) { + btrfs_print_leaf(path->nodes[0]); + btrfs_err(info, + "unable to find ref byte nr %llu parent %llu root %llu owner %llu offset %llu", + bytenr, parent, root_objectid, owner_objectid, + owner_offset); + btrfs_abort_transaction(trans, ret); + goto out; + } else { + btrfs_abort_transaction(trans, ret); + goto out; + } + + leaf = path->nodes[0]; + item_size = btrfs_item_size_nr(leaf, extent_slot); + if (unlikely(item_size < sizeof(*ei))) { + ret = -EINVAL; + btrfs_print_v0_err(info); + btrfs_abort_transaction(trans, ret); + goto out; + } + ei = btrfs_item_ptr(leaf, extent_slot, + struct btrfs_extent_item); + if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID && + key.type == BTRFS_EXTENT_ITEM_KEY) { + struct btrfs_tree_block_info *bi; + if (item_size < sizeof(*ei) + sizeof(*bi)) { + btrfs_crit(info, +"invalid extent item size for key (%llu, %u, %llu) owner %llu, has %u expect >= %zu", + key.objectid, key.type, key.offset, + owner_objectid, item_size, + sizeof(*ei) + sizeof(*bi)); + btrfs_abort_transaction(trans, -EUCLEAN); + goto err_dump; + } + bi = (struct btrfs_tree_block_info *)(ei + 1); + WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi)); + } + + refs = btrfs_extent_refs(leaf, ei); + if (refs < refs_to_drop) { + btrfs_crit(info, + "trying to drop %d refs but we only have %llu for bytenr %llu", + refs_to_drop, refs, bytenr); + btrfs_abort_transaction(trans, -EUCLEAN); + goto err_dump; + } + refs -= refs_to_drop; + + if (refs > 0) { + if (extent_op) + __run_delayed_extent_op(extent_op, leaf, ei); + /* + * In the case of inline back ref, reference count will + * be updated by remove_extent_backref + */ + if (iref) { + if (!found_extent) { + btrfs_crit(info, +"invalid iref, got inlined extent ref but no EXTENT/METADATA_ITEM found"); + btrfs_abort_transaction(trans, -EUCLEAN); + goto err_dump; + } + } else { + btrfs_set_extent_refs(leaf, ei, refs); + btrfs_mark_buffer_dirty(leaf); + } + if (found_extent) { + ret = remove_extent_backref(trans, path, iref, + refs_to_drop, is_data, + &last_ref); + if (ret) { + btrfs_abort_transaction(trans, ret); + goto out; + } + } + } else { + /* In this branch refs == 1 */ + if (found_extent) { + if (is_data && refs_to_drop != + extent_data_ref_count(path, iref)) { + btrfs_crit(info, + "invalid refs_to_drop, current refs %u refs_to_drop %u", + extent_data_ref_count(path, iref), + refs_to_drop); + btrfs_abort_transaction(trans, -EUCLEAN); + goto err_dump; + } + if (iref) { + if (path->slots[0] != extent_slot) { + btrfs_crit(info, +"invalid iref, extent item key (%llu %u %llu) doesn't have wanted iref", + key.objectid, key.type, + key.offset); + btrfs_abort_transaction(trans, -EUCLEAN); + goto err_dump; + } + } else { + /* + * No inline ref, we must be at SHARED_* item, + * And it's single ref, it must be: + * | extent_slot ||extent_slot + 1| + * [ EXTENT/METADATA_ITEM ][ SHARED_* ITEM ] + */ + if (path->slots[0] != extent_slot + 1) { + btrfs_crit(info, + "invalid SHARED_* item, previous item is not EXTENT/METADATA_ITEM"); + btrfs_abort_transaction(trans, -EUCLEAN); + goto err_dump; + } + path->slots[0] = extent_slot; + num_to_del = 2; + } + } + + last_ref = 1; + ret = btrfs_del_items(trans, extent_root, path, path->slots[0], + num_to_del); + if (ret) { + btrfs_abort_transaction(trans, ret); + goto out; + } + btrfs_release_path(path); + + if (is_data) { + ret = btrfs_del_csums(trans, info->csum_root, bytenr, + num_bytes); + if (ret) { + btrfs_abort_transaction(trans, ret); + goto out; + } + } + + ret = add_to_free_space_tree(trans, bytenr, num_bytes); + if (ret) { + btrfs_abort_transaction(trans, ret); + goto out; + } + + ret = btrfs_update_block_group(trans, bytenr, num_bytes, 0); + if (ret) { + btrfs_abort_transaction(trans, ret); + goto out; + } + } + btrfs_release_path(path); + +out: + btrfs_free_path(path); + return ret; +err_dump: + /* + * Leaf dump can take up a lot of log buffer, so we only do full leaf + * dump for debug build. + */ + if (IS_ENABLED(CONFIG_BTRFS_DEBUG)) { + btrfs_crit(info, "path->slots[0]=%d extent_slot=%d", + path->slots[0], extent_slot); + btrfs_print_leaf(path->nodes[0]); + } + + btrfs_free_path(path); + return -EUCLEAN; +} + +/* + * when we free an block, it is possible (and likely) that we free the last + * delayed ref for that extent as well. This searches the delayed ref tree for + * a given extent, and if there are no other delayed refs to be processed, it + * removes it from the tree. + */ +static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans, + u64 bytenr) +{ + struct btrfs_delayed_ref_head *head; + struct btrfs_delayed_ref_root *delayed_refs; + int ret = 0; + + delayed_refs = &trans->transaction->delayed_refs; + spin_lock(&delayed_refs->lock); + head = btrfs_find_delayed_ref_head(delayed_refs, bytenr); + if (!head) + goto out_delayed_unlock; + + spin_lock(&head->lock); + if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root)) + goto out; + + if (cleanup_extent_op(head) != NULL) + goto out; + + /* + * waiting for the lock here would deadlock. If someone else has it + * locked they are already in the process of dropping it anyway + */ + if (!mutex_trylock(&head->mutex)) + goto out; + + btrfs_delete_ref_head(delayed_refs, head); + head->processing = 0; + + spin_unlock(&head->lock); + spin_unlock(&delayed_refs->lock); + + BUG_ON(head->extent_op); + if (head->must_insert_reserved) + ret = 1; + + btrfs_cleanup_ref_head_accounting(trans->fs_info, delayed_refs, head); + mutex_unlock(&head->mutex); + btrfs_put_delayed_ref_head(head); + return ret; +out: + spin_unlock(&head->lock); + +out_delayed_unlock: + spin_unlock(&delayed_refs->lock); + return 0; +} + +void btrfs_free_tree_block(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct extent_buffer *buf, + u64 parent, int last_ref) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_ref generic_ref = { 0 }; + int ret; + + btrfs_init_generic_ref(&generic_ref, BTRFS_DROP_DELAYED_REF, + buf->start, buf->len, parent); + btrfs_init_tree_ref(&generic_ref, btrfs_header_level(buf), + root->root_key.objectid); + + if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) { + btrfs_ref_tree_mod(fs_info, &generic_ref); + ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, NULL); + BUG_ON(ret); /* -ENOMEM */ + } + + if (last_ref && btrfs_header_generation(buf) == trans->transid) { + struct btrfs_block_group *cache; + + if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) { + ret = check_ref_cleanup(trans, buf->start); + if (!ret) + goto out; + } + + cache = btrfs_lookup_block_group(fs_info, buf->start); + + if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) { + pin_down_extent(trans, cache, buf->start, buf->len, 1); + btrfs_put_block_group(cache); + goto out; + } + + WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)); + + btrfs_add_free_space(cache, buf->start, buf->len); + btrfs_free_reserved_bytes(cache, buf->len, 0); + btrfs_put_block_group(cache); + trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len); + } +out: + if (last_ref) { + /* + * Deleting the buffer, clear the corrupt flag since it doesn't + * matter anymore. + */ + clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags); + } +} + +/* Can return -ENOMEM */ +int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_ref *ref) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + int ret; + + if (btrfs_is_testing(fs_info)) + return 0; + + /* + * tree log blocks never actually go into the extent allocation + * tree, just update pinning info and exit early. + */ + if ((ref->type == BTRFS_REF_METADATA && + ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID) || + (ref->type == BTRFS_REF_DATA && + ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID)) { + /* unlocks the pinned mutex */ + btrfs_pin_extent(trans, ref->bytenr, ref->len, 1); + ret = 0; + } else if (ref->type == BTRFS_REF_METADATA) { + ret = btrfs_add_delayed_tree_ref(trans, ref, NULL); + } else { + ret = btrfs_add_delayed_data_ref(trans, ref, 0); + } + + if (!((ref->type == BTRFS_REF_METADATA && + ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID) || + (ref->type == BTRFS_REF_DATA && + ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID))) + btrfs_ref_tree_mod(fs_info, ref); + + return ret; +} + +enum btrfs_loop_type { + LOOP_CACHING_NOWAIT, + LOOP_CACHING_WAIT, + LOOP_ALLOC_CHUNK, + LOOP_NO_EMPTY_SIZE, +}; + +static inline void +btrfs_lock_block_group(struct btrfs_block_group *cache, + int delalloc) +{ + if (delalloc) + down_read(&cache->data_rwsem); +} + +static inline void btrfs_grab_block_group(struct btrfs_block_group *cache, + int delalloc) +{ + btrfs_get_block_group(cache); + if (delalloc) + down_read(&cache->data_rwsem); +} + +static struct btrfs_block_group *btrfs_lock_cluster( + struct btrfs_block_group *block_group, + struct btrfs_free_cluster *cluster, + int delalloc) + __acquires(&cluster->refill_lock) +{ + struct btrfs_block_group *used_bg = NULL; + + spin_lock(&cluster->refill_lock); + while (1) { + used_bg = cluster->block_group; + if (!used_bg) + return NULL; + + if (used_bg == block_group) + return used_bg; + + btrfs_get_block_group(used_bg); + + if (!delalloc) + return used_bg; + + if (down_read_trylock(&used_bg->data_rwsem)) + return used_bg; + + spin_unlock(&cluster->refill_lock); + + /* We should only have one-level nested. */ + down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING); + + spin_lock(&cluster->refill_lock); + if (used_bg == cluster->block_group) + return used_bg; + + up_read(&used_bg->data_rwsem); + btrfs_put_block_group(used_bg); + } +} + +static inline void +btrfs_release_block_group(struct btrfs_block_group *cache, + int delalloc) +{ + if (delalloc) + up_read(&cache->data_rwsem); + btrfs_put_block_group(cache); +} + +enum btrfs_extent_allocation_policy { + BTRFS_EXTENT_ALLOC_CLUSTERED, +}; + +/* + * Structure used internally for find_free_extent() function. Wraps needed + * parameters. + */ +struct find_free_extent_ctl { + /* Basic allocation info */ + u64 num_bytes; + u64 empty_size; + u64 flags; + int delalloc; + + /* Where to start the search inside the bg */ + u64 search_start; + + /* For clustered allocation */ + u64 empty_cluster; + struct btrfs_free_cluster *last_ptr; + bool use_cluster; + + bool have_caching_bg; + bool orig_have_caching_bg; + + /* RAID index, converted from flags */ + int index; + + /* + * Current loop number, check find_free_extent_update_loop() for details + */ + int loop; + + /* + * Whether we're refilling a cluster, if true we need to re-search + * current block group but don't try to refill the cluster again. + */ + bool retry_clustered; + + /* + * Whether we're updating free space cache, if true we need to re-search + * current block group but don't try updating free space cache again. + */ + bool retry_unclustered; + + /* If current block group is cached */ + int cached; + + /* Max contiguous hole found */ + u64 max_extent_size; + + /* Total free space from free space cache, not always contiguous */ + u64 total_free_space; + + /* Found result */ + u64 found_offset; + + /* Hint where to start looking for an empty space */ + u64 hint_byte; + + /* Allocation policy */ + enum btrfs_extent_allocation_policy policy; +}; + + +/* + * Helper function for find_free_extent(). + * + * Return -ENOENT to inform caller that we need fallback to unclustered mode. + * Return -EAGAIN to inform caller that we need to re-search this block group + * Return >0 to inform caller that we find nothing + * Return 0 means we have found a location and set ffe_ctl->found_offset. + */ +static int find_free_extent_clustered(struct btrfs_block_group *bg, + struct find_free_extent_ctl *ffe_ctl, + struct btrfs_block_group **cluster_bg_ret) +{ + struct btrfs_block_group *cluster_bg; + struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr; + u64 aligned_cluster; + u64 offset; + int ret; + + cluster_bg = btrfs_lock_cluster(bg, last_ptr, ffe_ctl->delalloc); + if (!cluster_bg) + goto refill_cluster; + if (cluster_bg != bg && (cluster_bg->ro || + !block_group_bits(cluster_bg, ffe_ctl->flags))) + goto release_cluster; + + offset = btrfs_alloc_from_cluster(cluster_bg, last_ptr, + ffe_ctl->num_bytes, cluster_bg->start, + &ffe_ctl->max_extent_size); + if (offset) { + /* We have a block, we're done */ + spin_unlock(&last_ptr->refill_lock); + trace_btrfs_reserve_extent_cluster(cluster_bg, + ffe_ctl->search_start, ffe_ctl->num_bytes); + *cluster_bg_ret = cluster_bg; + ffe_ctl->found_offset = offset; + return 0; + } + WARN_ON(last_ptr->block_group != cluster_bg); + +release_cluster: + /* + * If we are on LOOP_NO_EMPTY_SIZE, we can't set up a new clusters, so + * lets just skip it and let the allocator find whatever block it can + * find. If we reach this point, we will have tried the cluster + * allocator plenty of times and not have found anything, so we are + * likely way too fragmented for the clustering stuff to find anything. + * + * However, if the cluster is taken from the current block group, + * release the cluster first, so that we stand a better chance of + * succeeding in the unclustered allocation. + */ + if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE && cluster_bg != bg) { + spin_unlock(&last_ptr->refill_lock); + btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc); + return -ENOENT; + } + + /* This cluster didn't work out, free it and start over */ + btrfs_return_cluster_to_free_space(NULL, last_ptr); + + if (cluster_bg != bg) + btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc); + +refill_cluster: + if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE) { + spin_unlock(&last_ptr->refill_lock); + return -ENOENT; + } + + aligned_cluster = max_t(u64, + ffe_ctl->empty_cluster + ffe_ctl->empty_size, + bg->full_stripe_len); + ret = btrfs_find_space_cluster(bg, last_ptr, ffe_ctl->search_start, + ffe_ctl->num_bytes, aligned_cluster); + if (ret == 0) { + /* Now pull our allocation out of this cluster */ + offset = btrfs_alloc_from_cluster(bg, last_ptr, + ffe_ctl->num_bytes, ffe_ctl->search_start, + &ffe_ctl->max_extent_size); + if (offset) { + /* We found one, proceed */ + spin_unlock(&last_ptr->refill_lock); + trace_btrfs_reserve_extent_cluster(bg, + ffe_ctl->search_start, + ffe_ctl->num_bytes); + ffe_ctl->found_offset = offset; + return 0; + } + } else if (!ffe_ctl->cached && ffe_ctl->loop > LOOP_CACHING_NOWAIT && + !ffe_ctl->retry_clustered) { + spin_unlock(&last_ptr->refill_lock); + + ffe_ctl->retry_clustered = true; + btrfs_wait_block_group_cache_progress(bg, ffe_ctl->num_bytes + + ffe_ctl->empty_cluster + ffe_ctl->empty_size); + return -EAGAIN; + } + /* + * At this point we either didn't find a cluster or we weren't able to + * allocate a block from our cluster. Free the cluster we've been + * trying to use, and go to the next block group. + */ + btrfs_return_cluster_to_free_space(NULL, last_ptr); + spin_unlock(&last_ptr->refill_lock); + return 1; +} + +/* + * Return >0 to inform caller that we find nothing + * Return 0 when we found an free extent and set ffe_ctrl->found_offset + * Return -EAGAIN to inform caller that we need to re-search this block group + */ +static int find_free_extent_unclustered(struct btrfs_block_group *bg, + struct find_free_extent_ctl *ffe_ctl) +{ + struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr; + u64 offset; + + /* + * We are doing an unclustered allocation, set the fragmented flag so + * we don't bother trying to setup a cluster again until we get more + * space. + */ + if (unlikely(last_ptr)) { + spin_lock(&last_ptr->lock); + last_ptr->fragmented = 1; + spin_unlock(&last_ptr->lock); + } + if (ffe_ctl->cached) { + struct btrfs_free_space_ctl *free_space_ctl; + + free_space_ctl = bg->free_space_ctl; + spin_lock(&free_space_ctl->tree_lock); + if (free_space_ctl->free_space < + ffe_ctl->num_bytes + ffe_ctl->empty_cluster + + ffe_ctl->empty_size) { + ffe_ctl->total_free_space = max_t(u64, + ffe_ctl->total_free_space, + free_space_ctl->free_space); + spin_unlock(&free_space_ctl->tree_lock); + return 1; + } + spin_unlock(&free_space_ctl->tree_lock); + } + + offset = btrfs_find_space_for_alloc(bg, ffe_ctl->search_start, + ffe_ctl->num_bytes, ffe_ctl->empty_size, + &ffe_ctl->max_extent_size); + + /* + * If we didn't find a chunk, and we haven't failed on this block group + * before, and this block group is in the middle of caching and we are + * ok with waiting, then go ahead and wait for progress to be made, and + * set @retry_unclustered to true. + * + * If @retry_unclustered is true then we've already waited on this + * block group once and should move on to the next block group. + */ + if (!offset && !ffe_ctl->retry_unclustered && !ffe_ctl->cached && + ffe_ctl->loop > LOOP_CACHING_NOWAIT) { + btrfs_wait_block_group_cache_progress(bg, ffe_ctl->num_bytes + + ffe_ctl->empty_size); + ffe_ctl->retry_unclustered = true; + return -EAGAIN; + } else if (!offset) { + return 1; + } + ffe_ctl->found_offset = offset; + return 0; +} + +static int do_allocation_clustered(struct btrfs_block_group *block_group, + struct find_free_extent_ctl *ffe_ctl, + struct btrfs_block_group **bg_ret) +{ + int ret; + + /* We want to try and use the cluster allocator, so lets look there */ + if (ffe_ctl->last_ptr && ffe_ctl->use_cluster) { + ret = find_free_extent_clustered(block_group, ffe_ctl, bg_ret); + if (ret >= 0 || ret == -EAGAIN) + return ret; + /* ret == -ENOENT case falls through */ + } + + return find_free_extent_unclustered(block_group, ffe_ctl); +} + +static int do_allocation(struct btrfs_block_group *block_group, + struct find_free_extent_ctl *ffe_ctl, + struct btrfs_block_group **bg_ret) +{ + switch (ffe_ctl->policy) { + case BTRFS_EXTENT_ALLOC_CLUSTERED: + return do_allocation_clustered(block_group, ffe_ctl, bg_ret); + default: + BUG(); + } +} + +static void release_block_group(struct btrfs_block_group *block_group, + struct find_free_extent_ctl *ffe_ctl, + int delalloc) +{ + switch (ffe_ctl->policy) { + case BTRFS_EXTENT_ALLOC_CLUSTERED: + ffe_ctl->retry_clustered = false; + ffe_ctl->retry_unclustered = false; + break; + default: + BUG(); + } + + BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) != + ffe_ctl->index); + btrfs_release_block_group(block_group, delalloc); +} + +static void found_extent_clustered(struct find_free_extent_ctl *ffe_ctl, + struct btrfs_key *ins) +{ + struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr; + + if (!ffe_ctl->use_cluster && last_ptr) { + spin_lock(&last_ptr->lock); + last_ptr->window_start = ins->objectid; + spin_unlock(&last_ptr->lock); + } +} + +static void found_extent(struct find_free_extent_ctl *ffe_ctl, + struct btrfs_key *ins) +{ + switch (ffe_ctl->policy) { + case BTRFS_EXTENT_ALLOC_CLUSTERED: + found_extent_clustered(ffe_ctl, ins); + break; + default: + BUG(); + } +} + +static int chunk_allocation_failed(struct find_free_extent_ctl *ffe_ctl) +{ + switch (ffe_ctl->policy) { + case BTRFS_EXTENT_ALLOC_CLUSTERED: + /* + * If we can't allocate a new chunk we've already looped through + * at least once, move on to the NO_EMPTY_SIZE case. + */ + ffe_ctl->loop = LOOP_NO_EMPTY_SIZE; + return 0; + default: + BUG(); + } +} + +/* + * Return >0 means caller needs to re-search for free extent + * Return 0 means we have the needed free extent. + * Return <0 means we failed to locate any free extent. + */ +static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info, + struct btrfs_key *ins, + struct find_free_extent_ctl *ffe_ctl, + bool full_search) +{ + struct btrfs_root *root = fs_info->extent_root; + int ret; + + if ((ffe_ctl->loop == LOOP_CACHING_NOWAIT) && + ffe_ctl->have_caching_bg && !ffe_ctl->orig_have_caching_bg) + ffe_ctl->orig_have_caching_bg = true; + + if (!ins->objectid && ffe_ctl->loop >= LOOP_CACHING_WAIT && + ffe_ctl->have_caching_bg) + return 1; + + if (!ins->objectid && ++(ffe_ctl->index) < BTRFS_NR_RAID_TYPES) + return 1; + + if (ins->objectid) { + found_extent(ffe_ctl, ins); + return 0; + } + + /* + * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking + * caching kthreads as we move along + * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching + * LOOP_ALLOC_CHUNK, force a chunk allocation and try again + * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try + * again + */ + if (ffe_ctl->loop < LOOP_NO_EMPTY_SIZE) { + ffe_ctl->index = 0; + if (ffe_ctl->loop == LOOP_CACHING_NOWAIT) { + /* + * We want to skip the LOOP_CACHING_WAIT step if we + * don't have any uncached bgs and we've already done a + * full search through. + */ + if (ffe_ctl->orig_have_caching_bg || !full_search) + ffe_ctl->loop = LOOP_CACHING_WAIT; + else + ffe_ctl->loop = LOOP_ALLOC_CHUNK; + } else { + ffe_ctl->loop++; + } + + if (ffe_ctl->loop == LOOP_ALLOC_CHUNK) { + struct btrfs_trans_handle *trans; + int exist = 0; + + trans = current->journal_info; + if (trans) + exist = 1; + else + trans = btrfs_join_transaction(root); + + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + return ret; + } + + ret = btrfs_chunk_alloc(trans, ffe_ctl->flags, + CHUNK_ALLOC_FORCE); + + /* Do not bail out on ENOSPC since we can do more. */ + if (ret == -ENOSPC) + ret = chunk_allocation_failed(ffe_ctl); + else if (ret < 0) + btrfs_abort_transaction(trans, ret); + else + ret = 0; + if (!exist) + btrfs_end_transaction(trans); + if (ret) + return ret; + } + + if (ffe_ctl->loop == LOOP_NO_EMPTY_SIZE) { + if (ffe_ctl->policy != BTRFS_EXTENT_ALLOC_CLUSTERED) + return -ENOSPC; + + /* + * Don't loop again if we already have no empty_size and + * no empty_cluster. + */ + if (ffe_ctl->empty_size == 0 && + ffe_ctl->empty_cluster == 0) + return -ENOSPC; + ffe_ctl->empty_size = 0; + ffe_ctl->empty_cluster = 0; + } + return 1; + } + return -ENOSPC; +} + +static int prepare_allocation_clustered(struct btrfs_fs_info *fs_info, + struct find_free_extent_ctl *ffe_ctl, + struct btrfs_space_info *space_info, + struct btrfs_key *ins) +{ + /* + * If our free space is heavily fragmented we may not be able to make + * big contiguous allocations, so instead of doing the expensive search + * for free space, simply return ENOSPC with our max_extent_size so we + * can go ahead and search for a more manageable chunk. + * + * If our max_extent_size is large enough for our allocation simply + * disable clustering since we will likely not be able to find enough + * space to create a cluster and induce latency trying. + */ + if (space_info->max_extent_size) { + spin_lock(&space_info->lock); + if (space_info->max_extent_size && + ffe_ctl->num_bytes > space_info->max_extent_size) { + ins->offset = space_info->max_extent_size; + spin_unlock(&space_info->lock); + return -ENOSPC; + } else if (space_info->max_extent_size) { + ffe_ctl->use_cluster = false; + } + spin_unlock(&space_info->lock); + } + + ffe_ctl->last_ptr = fetch_cluster_info(fs_info, space_info, + &ffe_ctl->empty_cluster); + if (ffe_ctl->last_ptr) { + struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr; + + spin_lock(&last_ptr->lock); + if (last_ptr->block_group) + ffe_ctl->hint_byte = last_ptr->window_start; + if (last_ptr->fragmented) { + /* + * We still set window_start so we can keep track of the + * last place we found an allocation to try and save + * some time. + */ + ffe_ctl->hint_byte = last_ptr->window_start; + ffe_ctl->use_cluster = false; + } + spin_unlock(&last_ptr->lock); + } + + return 0; +} + +static int prepare_allocation(struct btrfs_fs_info *fs_info, + struct find_free_extent_ctl *ffe_ctl, + struct btrfs_space_info *space_info, + struct btrfs_key *ins) +{ + switch (ffe_ctl->policy) { + case BTRFS_EXTENT_ALLOC_CLUSTERED: + return prepare_allocation_clustered(fs_info, ffe_ctl, + space_info, ins); + default: + BUG(); + } +} + +/* + * walks the btree of allocated extents and find a hole of a given size. + * The key ins is changed to record the hole: + * ins->objectid == start position + * ins->flags = BTRFS_EXTENT_ITEM_KEY + * ins->offset == the size of the hole. + * Any available blocks before search_start are skipped. + * + * If there is no suitable free space, we will record the max size of + * the free space extent currently. + * + * The overall logic and call chain: + * + * find_free_extent() + * |- Iterate through all block groups + * | |- Get a valid block group + * | |- Try to do clustered allocation in that block group + * | |- Try to do unclustered allocation in that block group + * | |- Check if the result is valid + * | | |- If valid, then exit + * | |- Jump to next block group + * | + * |- Push harder to find free extents + * |- If not found, re-iterate all block groups + */ +static noinline int find_free_extent(struct btrfs_root *root, + u64 ram_bytes, u64 num_bytes, u64 empty_size, + u64 hint_byte_orig, struct btrfs_key *ins, + u64 flags, int delalloc) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + int ret = 0; + int cache_block_group_error = 0; + struct btrfs_block_group *block_group = NULL; + struct find_free_extent_ctl ffe_ctl = {0}; + struct btrfs_space_info *space_info; + bool full_search = false; + + WARN_ON(num_bytes < fs_info->sectorsize); + + ffe_ctl.num_bytes = num_bytes; + ffe_ctl.empty_size = empty_size; + ffe_ctl.flags = flags; + ffe_ctl.search_start = 0; + ffe_ctl.delalloc = delalloc; + ffe_ctl.index = btrfs_bg_flags_to_raid_index(flags); + ffe_ctl.have_caching_bg = false; + ffe_ctl.orig_have_caching_bg = false; + ffe_ctl.found_offset = 0; + ffe_ctl.hint_byte = hint_byte_orig; + ffe_ctl.policy = BTRFS_EXTENT_ALLOC_CLUSTERED; + + /* For clustered allocation */ + ffe_ctl.retry_clustered = false; + ffe_ctl.retry_unclustered = false; + ffe_ctl.last_ptr = NULL; + ffe_ctl.use_cluster = true; + + ins->type = BTRFS_EXTENT_ITEM_KEY; + ins->objectid = 0; + ins->offset = 0; + + trace_find_free_extent(root, num_bytes, empty_size, flags); + + space_info = btrfs_find_space_info(fs_info, flags); + if (!space_info) { + btrfs_err(fs_info, "No space info for %llu", flags); + return -ENOSPC; + } + + ret = prepare_allocation(fs_info, &ffe_ctl, space_info, ins); + if (ret < 0) + return ret; + + ffe_ctl.search_start = max(ffe_ctl.search_start, + first_logical_byte(fs_info, 0)); + ffe_ctl.search_start = max(ffe_ctl.search_start, ffe_ctl.hint_byte); + if (ffe_ctl.search_start == ffe_ctl.hint_byte) { + block_group = btrfs_lookup_block_group(fs_info, + ffe_ctl.search_start); + /* + * we don't want to use the block group if it doesn't match our + * allocation bits, or if its not cached. + * + * However if we are re-searching with an ideal block group + * picked out then we don't care that the block group is cached. + */ + if (block_group && block_group_bits(block_group, flags) && + block_group->cached != BTRFS_CACHE_NO) { + down_read(&space_info->groups_sem); + if (list_empty(&block_group->list) || + block_group->ro) { + /* + * someone is removing this block group, + * we can't jump into the have_block_group + * target because our list pointers are not + * valid + */ + btrfs_put_block_group(block_group); + up_read(&space_info->groups_sem); + } else { + ffe_ctl.index = btrfs_bg_flags_to_raid_index( + block_group->flags); + btrfs_lock_block_group(block_group, delalloc); + goto have_block_group; + } + } else if (block_group) { + btrfs_put_block_group(block_group); + } + } +search: + ffe_ctl.have_caching_bg = false; + if (ffe_ctl.index == btrfs_bg_flags_to_raid_index(flags) || + ffe_ctl.index == 0) + full_search = true; + down_read(&space_info->groups_sem); + list_for_each_entry(block_group, + &space_info->block_groups[ffe_ctl.index], list) { + struct btrfs_block_group *bg_ret; + + /* If the block group is read-only, we can skip it entirely. */ + if (unlikely(block_group->ro)) + continue; + + btrfs_grab_block_group(block_group, delalloc); + ffe_ctl.search_start = block_group->start; + + /* + * this can happen if we end up cycling through all the + * raid types, but we want to make sure we only allocate + * for the proper type. + */ + if (!block_group_bits(block_group, flags)) { + u64 extra = BTRFS_BLOCK_GROUP_DUP | + BTRFS_BLOCK_GROUP_RAID1_MASK | + BTRFS_BLOCK_GROUP_RAID56_MASK | + BTRFS_BLOCK_GROUP_RAID10; + + /* + * if they asked for extra copies and this block group + * doesn't provide them, bail. This does allow us to + * fill raid0 from raid1. + */ + if ((flags & extra) && !(block_group->flags & extra)) + goto loop; + + /* + * This block group has different flags than we want. + * It's possible that we have MIXED_GROUP flag but no + * block group is mixed. Just skip such block group. + */ + btrfs_release_block_group(block_group, delalloc); + continue; + } + +have_block_group: + ffe_ctl.cached = btrfs_block_group_done(block_group); + if (unlikely(!ffe_ctl.cached)) { + ffe_ctl.have_caching_bg = true; + ret = btrfs_cache_block_group(block_group, 0); + + /* + * If we get ENOMEM here or something else we want to + * try other block groups, because it may not be fatal. + * However if we can't find anything else we need to + * save our return here so that we return the actual + * error that caused problems, not ENOSPC. + */ + if (ret < 0) { + if (!cache_block_group_error) + cache_block_group_error = ret; + ret = 0; + goto loop; + } + ret = 0; + } + + if (unlikely(block_group->cached == BTRFS_CACHE_ERROR)) { + if (!cache_block_group_error) + cache_block_group_error = -EIO; + goto loop; + } + + bg_ret = NULL; + ret = do_allocation(block_group, &ffe_ctl, &bg_ret); + if (ret == 0) { + if (bg_ret && bg_ret != block_group) { + btrfs_release_block_group(block_group, delalloc); + block_group = bg_ret; + } + } else if (ret == -EAGAIN) { + goto have_block_group; + } else if (ret > 0) { + goto loop; + } + + /* Checks */ + ffe_ctl.search_start = round_up(ffe_ctl.found_offset, + fs_info->stripesize); + + /* move on to the next group */ + if (ffe_ctl.search_start + num_bytes > + block_group->start + block_group->length) { + btrfs_add_free_space(block_group, ffe_ctl.found_offset, + num_bytes); + goto loop; + } + + if (ffe_ctl.found_offset < ffe_ctl.search_start) + btrfs_add_free_space(block_group, ffe_ctl.found_offset, + ffe_ctl.search_start - ffe_ctl.found_offset); + + ret = btrfs_add_reserved_bytes(block_group, ram_bytes, + num_bytes, delalloc); + if (ret == -EAGAIN) { + btrfs_add_free_space(block_group, ffe_ctl.found_offset, + num_bytes); + goto loop; + } + btrfs_inc_block_group_reservations(block_group); + + /* we are all good, lets return */ + ins->objectid = ffe_ctl.search_start; + ins->offset = num_bytes; + + trace_btrfs_reserve_extent(block_group, ffe_ctl.search_start, + num_bytes); + btrfs_release_block_group(block_group, delalloc); + break; +loop: + release_block_group(block_group, &ffe_ctl, delalloc); + cond_resched(); + } + up_read(&space_info->groups_sem); + + ret = find_free_extent_update_loop(fs_info, ins, &ffe_ctl, full_search); + if (ret > 0) + goto search; + + if (ret == -ENOSPC && !cache_block_group_error) { + /* + * Use ffe_ctl->total_free_space as fallback if we can't find + * any contiguous hole. + */ + if (!ffe_ctl.max_extent_size) + ffe_ctl.max_extent_size = ffe_ctl.total_free_space; + spin_lock(&space_info->lock); + space_info->max_extent_size = ffe_ctl.max_extent_size; + spin_unlock(&space_info->lock); + ins->offset = ffe_ctl.max_extent_size; + } else if (ret == -ENOSPC) { + ret = cache_block_group_error; + } + return ret; +} + +/* + * btrfs_reserve_extent - entry point to the extent allocator. Tries to find a + * hole that is at least as big as @num_bytes. + * + * @root - The root that will contain this extent + * + * @ram_bytes - The amount of space in ram that @num_bytes take. This + * is used for accounting purposes. This value differs + * from @num_bytes only in the case of compressed extents. + * + * @num_bytes - Number of bytes to allocate on-disk. + * + * @min_alloc_size - Indicates the minimum amount of space that the + * allocator should try to satisfy. In some cases + * @num_bytes may be larger than what is required and if + * the filesystem is fragmented then allocation fails. + * However, the presence of @min_alloc_size gives a + * chance to try and satisfy the smaller allocation. + * + * @empty_size - A hint that you plan on doing more COW. This is the + * size in bytes the allocator should try to find free + * next to the block it returns. This is just a hint and + * may be ignored by the allocator. + * + * @hint_byte - Hint to the allocator to start searching above the byte + * address passed. It might be ignored. + * + * @ins - This key is modified to record the found hole. It will + * have the following values: + * ins->objectid == start position + * ins->flags = BTRFS_EXTENT_ITEM_KEY + * ins->offset == the size of the hole. + * + * @is_data - Boolean flag indicating whether an extent is + * allocated for data (true) or metadata (false) + * + * @delalloc - Boolean flag indicating whether this allocation is for + * delalloc or not. If 'true' data_rwsem of block groups + * is going to be acquired. + * + * + * Returns 0 when an allocation succeeded or < 0 when an error occurred. In + * case -ENOSPC is returned then @ins->offset will contain the size of the + * largest available hole the allocator managed to find. + */ +int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes, + u64 num_bytes, u64 min_alloc_size, + u64 empty_size, u64 hint_byte, + struct btrfs_key *ins, int is_data, int delalloc) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + bool final_tried = num_bytes == min_alloc_size; + u64 flags; + int ret; + + flags = get_alloc_profile_by_root(root, is_data); +again: + WARN_ON(num_bytes < fs_info->sectorsize); + ret = find_free_extent(root, ram_bytes, num_bytes, empty_size, + hint_byte, ins, flags, delalloc); + if (!ret && !is_data) { + btrfs_dec_block_group_reservations(fs_info, ins->objectid); + } else if (ret == -ENOSPC) { + if (!final_tried && ins->offset) { + num_bytes = min(num_bytes >> 1, ins->offset); + num_bytes = round_down(num_bytes, + fs_info->sectorsize); + num_bytes = max(num_bytes, min_alloc_size); + ram_bytes = num_bytes; + if (num_bytes == min_alloc_size) + final_tried = true; + goto again; + } else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) { + struct btrfs_space_info *sinfo; + + sinfo = btrfs_find_space_info(fs_info, flags); + btrfs_err(fs_info, + "allocation failed flags %llu, wanted %llu", + flags, num_bytes); + if (sinfo) + btrfs_dump_space_info(fs_info, sinfo, + num_bytes, 1); + } + } + + return ret; +} + +int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info, + u64 start, u64 len, int delalloc) +{ + struct btrfs_block_group *cache; + + cache = btrfs_lookup_block_group(fs_info, start); + if (!cache) { + btrfs_err(fs_info, "Unable to find block group for %llu", + start); + return -ENOSPC; + } + + btrfs_add_free_space(cache, start, len); + btrfs_free_reserved_bytes(cache, len, delalloc); + trace_btrfs_reserved_extent_free(fs_info, start, len); + + btrfs_put_block_group(cache); + return 0; +} + +int btrfs_pin_reserved_extent(struct btrfs_trans_handle *trans, u64 start, + u64 len) +{ + struct btrfs_block_group *cache; + int ret = 0; + + cache = btrfs_lookup_block_group(trans->fs_info, start); + if (!cache) { + btrfs_err(trans->fs_info, "unable to find block group for %llu", + start); + return -ENOSPC; + } + + ret = pin_down_extent(trans, cache, start, len, 1); + btrfs_put_block_group(cache); + return ret; +} + +static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans, + u64 parent, u64 root_objectid, + u64 flags, u64 owner, u64 offset, + struct btrfs_key *ins, int ref_mod) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + int ret; + struct btrfs_extent_item *extent_item; + struct btrfs_extent_inline_ref *iref; + struct btrfs_path *path; + struct extent_buffer *leaf; + int type; + u32 size; + + if (parent > 0) + type = BTRFS_SHARED_DATA_REF_KEY; + else + type = BTRFS_EXTENT_DATA_REF_KEY; + + size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type); + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + path->leave_spinning = 1; + ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path, + ins, size); + if (ret) { + btrfs_free_path(path); + return ret; + } + + leaf = path->nodes[0]; + extent_item = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_extent_item); + btrfs_set_extent_refs(leaf, extent_item, ref_mod); + btrfs_set_extent_generation(leaf, extent_item, trans->transid); + btrfs_set_extent_flags(leaf, extent_item, + flags | BTRFS_EXTENT_FLAG_DATA); + + iref = (struct btrfs_extent_inline_ref *)(extent_item + 1); + btrfs_set_extent_inline_ref_type(leaf, iref, type); + if (parent > 0) { + struct btrfs_shared_data_ref *ref; + ref = (struct btrfs_shared_data_ref *)(iref + 1); + btrfs_set_extent_inline_ref_offset(leaf, iref, parent); + btrfs_set_shared_data_ref_count(leaf, ref, ref_mod); + } else { + struct btrfs_extent_data_ref *ref; + ref = (struct btrfs_extent_data_ref *)(&iref->offset); + btrfs_set_extent_data_ref_root(leaf, ref, root_objectid); + btrfs_set_extent_data_ref_objectid(leaf, ref, owner); + btrfs_set_extent_data_ref_offset(leaf, ref, offset); + btrfs_set_extent_data_ref_count(leaf, ref, ref_mod); + } + + btrfs_mark_buffer_dirty(path->nodes[0]); + btrfs_free_path(path); + + ret = remove_from_free_space_tree(trans, ins->objectid, ins->offset); + if (ret) + return ret; + + ret = btrfs_update_block_group(trans, ins->objectid, ins->offset, 1); + if (ret) { /* -ENOENT, logic error */ + btrfs_err(fs_info, "update block group failed for %llu %llu", + ins->objectid, ins->offset); + BUG(); + } + trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid, ins->offset); + return ret; +} + +static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_node *node, + struct btrfs_delayed_extent_op *extent_op) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + int ret; + struct btrfs_extent_item *extent_item; + struct btrfs_key extent_key; + struct btrfs_tree_block_info *block_info; + struct btrfs_extent_inline_ref *iref; + struct btrfs_path *path; + struct extent_buffer *leaf; + struct btrfs_delayed_tree_ref *ref; + u32 size = sizeof(*extent_item) + sizeof(*iref); + u64 num_bytes; + u64 flags = extent_op->flags_to_set; + bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA); + + ref = btrfs_delayed_node_to_tree_ref(node); + + extent_key.objectid = node->bytenr; + if (skinny_metadata) { + extent_key.offset = ref->level; + extent_key.type = BTRFS_METADATA_ITEM_KEY; + num_bytes = fs_info->nodesize; + } else { + extent_key.offset = node->num_bytes; + extent_key.type = BTRFS_EXTENT_ITEM_KEY; + size += sizeof(*block_info); + num_bytes = node->num_bytes; + } + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + path->leave_spinning = 1; + ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path, + &extent_key, size); + if (ret) { + btrfs_free_path(path); + return ret; + } + + leaf = path->nodes[0]; + extent_item = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_extent_item); + btrfs_set_extent_refs(leaf, extent_item, 1); + btrfs_set_extent_generation(leaf, extent_item, trans->transid); + btrfs_set_extent_flags(leaf, extent_item, + flags | BTRFS_EXTENT_FLAG_TREE_BLOCK); + + if (skinny_metadata) { + iref = (struct btrfs_extent_inline_ref *)(extent_item + 1); + } else { + block_info = (struct btrfs_tree_block_info *)(extent_item + 1); + btrfs_set_tree_block_key(leaf, block_info, &extent_op->key); + btrfs_set_tree_block_level(leaf, block_info, ref->level); + iref = (struct btrfs_extent_inline_ref *)(block_info + 1); + } + + if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) { + BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)); + btrfs_set_extent_inline_ref_type(leaf, iref, + BTRFS_SHARED_BLOCK_REF_KEY); + btrfs_set_extent_inline_ref_offset(leaf, iref, ref->parent); + } else { + btrfs_set_extent_inline_ref_type(leaf, iref, + BTRFS_TREE_BLOCK_REF_KEY); + btrfs_set_extent_inline_ref_offset(leaf, iref, ref->root); + } + + btrfs_mark_buffer_dirty(leaf); + btrfs_free_path(path); + + ret = remove_from_free_space_tree(trans, extent_key.objectid, + num_bytes); + if (ret) + return ret; + + ret = btrfs_update_block_group(trans, extent_key.objectid, + fs_info->nodesize, 1); + if (ret) { /* -ENOENT, logic error */ + btrfs_err(fs_info, "update block group failed for %llu %llu", + extent_key.objectid, extent_key.offset); + BUG(); + } + + trace_btrfs_reserved_extent_alloc(fs_info, extent_key.objectid, + fs_info->nodesize); + return ret; +} + +int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans, + struct btrfs_root *root, u64 owner, + u64 offset, u64 ram_bytes, + struct btrfs_key *ins) +{ + struct btrfs_ref generic_ref = { 0 }; + + BUG_ON(root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID); + + btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT, + ins->objectid, ins->offset, 0); + btrfs_init_data_ref(&generic_ref, root->root_key.objectid, owner, offset); + btrfs_ref_tree_mod(root->fs_info, &generic_ref); + + return btrfs_add_delayed_data_ref(trans, &generic_ref, ram_bytes); +} + +/* + * this is used by the tree logging recovery code. It records that + * an extent has been allocated and makes sure to clear the free + * space cache bits as well + */ +int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans, + u64 root_objectid, u64 owner, u64 offset, + struct btrfs_key *ins) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + int ret; + struct btrfs_block_group *block_group; + struct btrfs_space_info *space_info; + + /* + * Mixed block groups will exclude before processing the log so we only + * need to do the exclude dance if this fs isn't mixed. + */ + if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) { + ret = __exclude_logged_extent(fs_info, ins->objectid, + ins->offset); + if (ret) + return ret; + } + + block_group = btrfs_lookup_block_group(fs_info, ins->objectid); + if (!block_group) + return -EINVAL; + + space_info = block_group->space_info; + spin_lock(&space_info->lock); + spin_lock(&block_group->lock); + space_info->bytes_reserved += ins->offset; + block_group->reserved += ins->offset; + spin_unlock(&block_group->lock); + spin_unlock(&space_info->lock); + + ret = alloc_reserved_file_extent(trans, 0, root_objectid, 0, owner, + offset, ins, 1); + if (ret) + btrfs_pin_extent(trans, ins->objectid, ins->offset, 1); + btrfs_put_block_group(block_group); + return ret; +} + +static struct extent_buffer * +btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root, + u64 bytenr, int level, u64 owner, + enum btrfs_lock_nesting nest) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct extent_buffer *buf; + + buf = btrfs_find_create_tree_block(fs_info, bytenr); + if (IS_ERR(buf)) + return buf; + + /* + * Extra safety check in case the extent tree is corrupted and extent + * allocator chooses to use a tree block which is already used and + * locked. + */ + if (buf->lock_owner == current->pid) { + btrfs_err_rl(fs_info, +"tree block %llu owner %llu already locked by pid=%d, extent tree corruption detected", + buf->start, btrfs_header_owner(buf), current->pid); + free_extent_buffer(buf); + return ERR_PTR(-EUCLEAN); + } + + btrfs_set_buffer_lockdep_class(owner, buf, level); + __btrfs_tree_lock(buf, nest); + btrfs_clean_tree_block(buf); + clear_bit(EXTENT_BUFFER_STALE, &buf->bflags); + + btrfs_set_lock_blocking_write(buf); + set_extent_buffer_uptodate(buf); + + memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header)); + btrfs_set_header_level(buf, level); + btrfs_set_header_bytenr(buf, buf->start); + btrfs_set_header_generation(buf, trans->transid); + btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV); + btrfs_set_header_owner(buf, owner); + write_extent_buffer_fsid(buf, fs_info->fs_devices->metadata_uuid); + write_extent_buffer_chunk_tree_uuid(buf, fs_info->chunk_tree_uuid); + if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) { + buf->log_index = root->log_transid % 2; + /* + * we allow two log transactions at a time, use different + * EXTENT bit to differentiate dirty pages. + */ + if (buf->log_index == 0) + set_extent_dirty(&root->dirty_log_pages, buf->start, + buf->start + buf->len - 1, GFP_NOFS); + else + set_extent_new(&root->dirty_log_pages, buf->start, + buf->start + buf->len - 1); + } else { + buf->log_index = -1; + set_extent_dirty(&trans->transaction->dirty_pages, buf->start, + buf->start + buf->len - 1, GFP_NOFS); + } + trans->dirty = true; + /* this returns a buffer locked for blocking */ + return buf; +} + +/* + * finds a free extent and does all the dirty work required for allocation + * returns the tree buffer or an ERR_PTR on error. + */ +struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + u64 parent, u64 root_objectid, + const struct btrfs_disk_key *key, + int level, u64 hint, + u64 empty_size, + enum btrfs_lock_nesting nest) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_key ins; + struct btrfs_block_rsv *block_rsv; + struct extent_buffer *buf; + struct btrfs_delayed_extent_op *extent_op; + struct btrfs_ref generic_ref = { 0 }; + u64 flags = 0; + int ret; + u32 blocksize = fs_info->nodesize; + bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA); + +#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS + if (btrfs_is_testing(fs_info)) { + buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr, + level, root_objectid, nest); + if (!IS_ERR(buf)) + root->alloc_bytenr += blocksize; + return buf; + } +#endif + + block_rsv = btrfs_use_block_rsv(trans, root, blocksize); + if (IS_ERR(block_rsv)) + return ERR_CAST(block_rsv); + + ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize, + empty_size, hint, &ins, 0, 0); + if (ret) + goto out_unuse; + + buf = btrfs_init_new_buffer(trans, root, ins.objectid, level, + root_objectid, nest); + if (IS_ERR(buf)) { + ret = PTR_ERR(buf); + goto out_free_reserved; + } + + if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) { + if (parent == 0) + parent = ins.objectid; + flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF; + } else + BUG_ON(parent > 0); + + if (root_objectid != BTRFS_TREE_LOG_OBJECTID) { + extent_op = btrfs_alloc_delayed_extent_op(); + if (!extent_op) { + ret = -ENOMEM; + goto out_free_buf; + } + if (key) + memcpy(&extent_op->key, key, sizeof(extent_op->key)); + else + memset(&extent_op->key, 0, sizeof(extent_op->key)); + extent_op->flags_to_set = flags; + extent_op->update_key = skinny_metadata ? false : true; + extent_op->update_flags = true; + extent_op->is_data = false; + extent_op->level = level; + + btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT, + ins.objectid, ins.offset, parent); + generic_ref.real_root = root->root_key.objectid; + btrfs_init_tree_ref(&generic_ref, level, root_objectid); + btrfs_ref_tree_mod(fs_info, &generic_ref); + ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, extent_op); + if (ret) + goto out_free_delayed; + } + return buf; + +out_free_delayed: + btrfs_free_delayed_extent_op(extent_op); +out_free_buf: + btrfs_tree_unlock(buf); + free_extent_buffer(buf); +out_free_reserved: + btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0); +out_unuse: + btrfs_unuse_block_rsv(fs_info, block_rsv, blocksize); + return ERR_PTR(ret); +} + +struct walk_control { + u64 refs[BTRFS_MAX_LEVEL]; + u64 flags[BTRFS_MAX_LEVEL]; + struct btrfs_key update_progress; + struct btrfs_key drop_progress; + int drop_level; + int stage; + int level; + int shared_level; + int update_ref; + int keep_locks; + int reada_slot; + int reada_count; + int restarted; +}; + +#define DROP_REFERENCE 1 +#define UPDATE_BACKREF 2 + +static noinline void reada_walk_down(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct walk_control *wc, + struct btrfs_path *path) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + u64 bytenr; + u64 generation; + u64 refs; + u64 flags; + u32 nritems; + struct btrfs_key key; + struct extent_buffer *eb; + int ret; + int slot; + int nread = 0; + + if (path->slots[wc->level] < wc->reada_slot) { + wc->reada_count = wc->reada_count * 2 / 3; + wc->reada_count = max(wc->reada_count, 2); + } else { + wc->reada_count = wc->reada_count * 3 / 2; + wc->reada_count = min_t(int, wc->reada_count, + BTRFS_NODEPTRS_PER_BLOCK(fs_info)); + } + + eb = path->nodes[wc->level]; + nritems = btrfs_header_nritems(eb); + + for (slot = path->slots[wc->level]; slot < nritems; slot++) { + if (nread >= wc->reada_count) + break; + + cond_resched(); + bytenr = btrfs_node_blockptr(eb, slot); + generation = btrfs_node_ptr_generation(eb, slot); + + if (slot == path->slots[wc->level]) + goto reada; + + if (wc->stage == UPDATE_BACKREF && + generation <= root->root_key.offset) + continue; + + /* We don't lock the tree block, it's OK to be racy here */ + ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, + wc->level - 1, 1, &refs, + &flags); + /* We don't care about errors in readahead. */ + if (ret < 0) + continue; + BUG_ON(refs == 0); + + if (wc->stage == DROP_REFERENCE) { + if (refs == 1) + goto reada; + + if (wc->level == 1 && + (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) + continue; + if (!wc->update_ref || + generation <= root->root_key.offset) + continue; + btrfs_node_key_to_cpu(eb, &key, slot); + ret = btrfs_comp_cpu_keys(&key, + &wc->update_progress); + if (ret < 0) + continue; + } else { + if (wc->level == 1 && + (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) + continue; + } +reada: + readahead_tree_block(fs_info, bytenr); + nread++; + } + wc->reada_slot = slot; +} + +/* + * helper to process tree block while walking down the tree. + * + * when wc->stage == UPDATE_BACKREF, this function updates + * back refs for pointers in the block. + * + * NOTE: return value 1 means we should stop walking down. + */ +static noinline int walk_down_proc(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, + struct walk_control *wc, int lookup_info) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + int level = wc->level; + struct extent_buffer *eb = path->nodes[level]; + u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF; + int ret; + + if (wc->stage == UPDATE_BACKREF && + btrfs_header_owner(eb) != root->root_key.objectid) + return 1; + + /* + * when reference count of tree block is 1, it won't increase + * again. once full backref flag is set, we never clear it. + */ + if (lookup_info && + ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) || + (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) { + BUG_ON(!path->locks[level]); + ret = btrfs_lookup_extent_info(trans, fs_info, + eb->start, level, 1, + &wc->refs[level], + &wc->flags[level]); + BUG_ON(ret == -ENOMEM); + if (ret) + return ret; + BUG_ON(wc->refs[level] == 0); + } + + if (wc->stage == DROP_REFERENCE) { + if (wc->refs[level] > 1) + return 1; + + if (path->locks[level] && !wc->keep_locks) { + btrfs_tree_unlock_rw(eb, path->locks[level]); + path->locks[level] = 0; + } + return 0; + } + + /* wc->stage == UPDATE_BACKREF */ + if (!(wc->flags[level] & flag)) { + BUG_ON(!path->locks[level]); + ret = btrfs_inc_ref(trans, root, eb, 1); + BUG_ON(ret); /* -ENOMEM */ + ret = btrfs_dec_ref(trans, root, eb, 0); + BUG_ON(ret); /* -ENOMEM */ + ret = btrfs_set_disk_extent_flags(trans, eb, flag, + btrfs_header_level(eb), 0); + BUG_ON(ret); /* -ENOMEM */ + wc->flags[level] |= flag; + } + + /* + * the block is shared by multiple trees, so it's not good to + * keep the tree lock + */ + if (path->locks[level] && level > 0) { + btrfs_tree_unlock_rw(eb, path->locks[level]); + path->locks[level] = 0; + } + return 0; +} + +/* + * This is used to verify a ref exists for this root to deal with a bug where we + * would have a drop_progress key that hadn't been updated properly. + */ +static int check_ref_exists(struct btrfs_trans_handle *trans, + struct btrfs_root *root, u64 bytenr, u64 parent, + int level) +{ + struct btrfs_path *path; + struct btrfs_extent_inline_ref *iref; + int ret; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + ret = lookup_extent_backref(trans, path, &iref, bytenr, + root->fs_info->nodesize, parent, + root->root_key.objectid, level, 0); + btrfs_free_path(path); + if (ret == -ENOENT) + return 0; + if (ret < 0) + return ret; + return 1; +} + +/* + * helper to process tree block pointer. + * + * when wc->stage == DROP_REFERENCE, this function checks + * reference count of the block pointed to. if the block + * is shared and we need update back refs for the subtree + * rooted at the block, this function changes wc->stage to + * UPDATE_BACKREF. if the block is shared and there is no + * need to update back, this function drops the reference + * to the block. + * + * NOTE: return value 1 means we should stop walking down. + */ +static noinline int do_walk_down(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, + struct walk_control *wc, int *lookup_info) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + u64 bytenr; + u64 generation; + u64 parent; + struct btrfs_key key; + struct btrfs_key first_key; + struct btrfs_ref ref = { 0 }; + struct extent_buffer *next; + int level = wc->level; + int reada = 0; + int ret = 0; + bool need_account = false; + + generation = btrfs_node_ptr_generation(path->nodes[level], + path->slots[level]); + /* + * if the lower level block was created before the snapshot + * was created, we know there is no need to update back refs + * for the subtree + */ + if (wc->stage == UPDATE_BACKREF && + generation <= root->root_key.offset) { + *lookup_info = 1; + return 1; + } + + bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]); + btrfs_node_key_to_cpu(path->nodes[level], &first_key, + path->slots[level]); + + next = find_extent_buffer(fs_info, bytenr); + if (!next) { + next = btrfs_find_create_tree_block(fs_info, bytenr); + if (IS_ERR(next)) + return PTR_ERR(next); + + btrfs_set_buffer_lockdep_class(root->root_key.objectid, next, + level - 1); + reada = 1; + } + btrfs_tree_lock(next); + btrfs_set_lock_blocking_write(next); + + ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1, + &wc->refs[level - 1], + &wc->flags[level - 1]); + if (ret < 0) + goto out_unlock; + + if (unlikely(wc->refs[level - 1] == 0)) { + btrfs_err(fs_info, "Missing references."); + ret = -EIO; + goto out_unlock; + } + *lookup_info = 0; + + if (wc->stage == DROP_REFERENCE) { + if (wc->refs[level - 1] > 1) { + need_account = true; + if (level == 1 && + (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF)) + goto skip; + + if (!wc->update_ref || + generation <= root->root_key.offset) + goto skip; + + btrfs_node_key_to_cpu(path->nodes[level], &key, + path->slots[level]); + ret = btrfs_comp_cpu_keys(&key, &wc->update_progress); + if (ret < 0) + goto skip; + + wc->stage = UPDATE_BACKREF; + wc->shared_level = level - 1; + } + } else { + if (level == 1 && + (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF)) + goto skip; + } + + if (!btrfs_buffer_uptodate(next, generation, 0)) { + btrfs_tree_unlock(next); + free_extent_buffer(next); + next = NULL; + *lookup_info = 1; + } + + if (!next) { + if (reada && level == 1) + reada_walk_down(trans, root, wc, path); + next = read_tree_block(fs_info, bytenr, generation, level - 1, + &first_key); + if (IS_ERR(next)) { + return PTR_ERR(next); + } else if (!extent_buffer_uptodate(next)) { + free_extent_buffer(next); + return -EIO; + } + btrfs_tree_lock(next); + btrfs_set_lock_blocking_write(next); + } + + level--; + ASSERT(level == btrfs_header_level(next)); + if (level != btrfs_header_level(next)) { + btrfs_err(root->fs_info, "mismatched level"); + ret = -EIO; + goto out_unlock; + } + path->nodes[level] = next; + path->slots[level] = 0; + path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING; + wc->level = level; + if (wc->level == 1) + wc->reada_slot = 0; + return 0; +skip: + wc->refs[level - 1] = 0; + wc->flags[level - 1] = 0; + if (wc->stage == DROP_REFERENCE) { + if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) { + parent = path->nodes[level]->start; + } else { + ASSERT(root->root_key.objectid == + btrfs_header_owner(path->nodes[level])); + if (root->root_key.objectid != + btrfs_header_owner(path->nodes[level])) { + btrfs_err(root->fs_info, + "mismatched block owner"); + ret = -EIO; + goto out_unlock; + } + parent = 0; + } + + /* + * If we had a drop_progress we need to verify the refs are set + * as expected. If we find our ref then we know that from here + * on out everything should be correct, and we can clear the + * ->restarted flag. + */ + if (wc->restarted) { + ret = check_ref_exists(trans, root, bytenr, parent, + level - 1); + if (ret < 0) + goto out_unlock; + if (ret == 0) + goto no_delete; + ret = 0; + wc->restarted = 0; + } + + /* + * Reloc tree doesn't contribute to qgroup numbers, and we have + * already accounted them at merge time (replace_path), + * thus we could skip expensive subtree trace here. + */ + if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID && + need_account) { + ret = btrfs_qgroup_trace_subtree(trans, next, + generation, level - 1); + if (ret) { + btrfs_err_rl(fs_info, + "Error %d accounting shared subtree. Quota is out of sync, rescan required.", + ret); + } + } + + /* + * We need to update the next key in our walk control so we can + * update the drop_progress key accordingly. We don't care if + * find_next_key doesn't find a key because that means we're at + * the end and are going to clean up now. + */ + wc->drop_level = level; + find_next_key(path, level, &wc->drop_progress); + + btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr, + fs_info->nodesize, parent); + btrfs_init_tree_ref(&ref, level - 1, root->root_key.objectid); + ret = btrfs_free_extent(trans, &ref); + if (ret) + goto out_unlock; + } +no_delete: + *lookup_info = 1; + ret = 1; + +out_unlock: + btrfs_tree_unlock(next); + free_extent_buffer(next); + + return ret; +} + +/* + * helper to process tree block while walking up the tree. + * + * when wc->stage == DROP_REFERENCE, this function drops + * reference count on the block. + * + * when wc->stage == UPDATE_BACKREF, this function changes + * wc->stage back to DROP_REFERENCE if we changed wc->stage + * to UPDATE_BACKREF previously while processing the block. + * + * NOTE: return value 1 means we should stop walking up. + */ +static noinline int walk_up_proc(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, + struct walk_control *wc) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + int ret; + int level = wc->level; + struct extent_buffer *eb = path->nodes[level]; + u64 parent = 0; + + if (wc->stage == UPDATE_BACKREF) { + BUG_ON(wc->shared_level < level); + if (level < wc->shared_level) + goto out; + + ret = find_next_key(path, level + 1, &wc->update_progress); + if (ret > 0) + wc->update_ref = 0; + + wc->stage = DROP_REFERENCE; + wc->shared_level = -1; + path->slots[level] = 0; + + /* + * check reference count again if the block isn't locked. + * we should start walking down the tree again if reference + * count is one. + */ + if (!path->locks[level]) { + BUG_ON(level == 0); + btrfs_tree_lock(eb); + btrfs_set_lock_blocking_write(eb); + path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING; + + ret = btrfs_lookup_extent_info(trans, fs_info, + eb->start, level, 1, + &wc->refs[level], + &wc->flags[level]); + if (ret < 0) { + btrfs_tree_unlock_rw(eb, path->locks[level]); + path->locks[level] = 0; + return ret; + } + BUG_ON(wc->refs[level] == 0); + if (wc->refs[level] == 1) { + btrfs_tree_unlock_rw(eb, path->locks[level]); + path->locks[level] = 0; + return 1; + } + } + } + + /* wc->stage == DROP_REFERENCE */ + BUG_ON(wc->refs[level] > 1 && !path->locks[level]); + + if (wc->refs[level] == 1) { + if (level == 0) { + if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) + ret = btrfs_dec_ref(trans, root, eb, 1); + else + ret = btrfs_dec_ref(trans, root, eb, 0); + BUG_ON(ret); /* -ENOMEM */ + if (is_fstree(root->root_key.objectid)) { + ret = btrfs_qgroup_trace_leaf_items(trans, eb); + if (ret) { + btrfs_err_rl(fs_info, + "error %d accounting leaf items, quota is out of sync, rescan required", + ret); + } + } + } + /* make block locked assertion in btrfs_clean_tree_block happy */ + if (!path->locks[level] && + btrfs_header_generation(eb) == trans->transid) { + btrfs_tree_lock(eb); + btrfs_set_lock_blocking_write(eb); + path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING; + } + btrfs_clean_tree_block(eb); + } + + if (eb == root->node) { + if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) + parent = eb->start; + else if (root->root_key.objectid != btrfs_header_owner(eb)) + goto owner_mismatch; + } else { + if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF) + parent = path->nodes[level + 1]->start; + else if (root->root_key.objectid != + btrfs_header_owner(path->nodes[level + 1])) + goto owner_mismatch; + } + + btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1); +out: + wc->refs[level] = 0; + wc->flags[level] = 0; + return 0; + +owner_mismatch: + btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu", + btrfs_header_owner(eb), root->root_key.objectid); + return -EUCLEAN; +} + +static noinline int walk_down_tree(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, + struct walk_control *wc) +{ + int level = wc->level; + int lookup_info = 1; + int ret; + + while (level >= 0) { + ret = walk_down_proc(trans, root, path, wc, lookup_info); + if (ret > 0) + break; + + if (level == 0) + break; + + if (path->slots[level] >= + btrfs_header_nritems(path->nodes[level])) + break; + + ret = do_walk_down(trans, root, path, wc, &lookup_info); + if (ret > 0) { + path->slots[level]++; + continue; + } else if (ret < 0) + return ret; + level = wc->level; + } + return 0; +} + +static noinline int walk_up_tree(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, + struct walk_control *wc, int max_level) +{ + int level = wc->level; + int ret; + + path->slots[level] = btrfs_header_nritems(path->nodes[level]); + while (level < max_level && path->nodes[level]) { + wc->level = level; + if (path->slots[level] + 1 < + btrfs_header_nritems(path->nodes[level])) { + path->slots[level]++; + return 0; + } else { + ret = walk_up_proc(trans, root, path, wc); + if (ret > 0) + return 0; + if (ret < 0) + return ret; + + if (path->locks[level]) { + btrfs_tree_unlock_rw(path->nodes[level], + path->locks[level]); + path->locks[level] = 0; + } + free_extent_buffer(path->nodes[level]); + path->nodes[level] = NULL; + level++; + } + } + return 1; +} + +/* + * drop a subvolume tree. + * + * this function traverses the tree freeing any blocks that only + * referenced by the tree. + * + * when a shared tree block is found. this function decreases its + * reference count by one. if update_ref is true, this function + * also make sure backrefs for the shared block and all lower level + * blocks are properly updated. + * + * If called with for_reloc == 0, may exit early with -EAGAIN + */ +int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_path *path; + struct btrfs_trans_handle *trans; + struct btrfs_root *tree_root = fs_info->tree_root; + struct btrfs_root_item *root_item = &root->root_item; + struct walk_control *wc; + struct btrfs_key key; + int err = 0; + int ret; + int level; + bool root_dropped = false; + + btrfs_debug(fs_info, "Drop subvolume %llu", root->root_key.objectid); + + path = btrfs_alloc_path(); + if (!path) { + err = -ENOMEM; + goto out; + } + + wc = kzalloc(sizeof(*wc), GFP_NOFS); + if (!wc) { + btrfs_free_path(path); + err = -ENOMEM; + goto out; + } + + /* + * Use join to avoid potential EINTR from transaction start. See + * wait_reserve_ticket and the whole reservation callchain. + */ + if (for_reloc) + trans = btrfs_join_transaction(tree_root); + else + trans = btrfs_start_transaction(tree_root, 0); + if (IS_ERR(trans)) { + err = PTR_ERR(trans); + goto out_free; + } + + err = btrfs_run_delayed_items(trans); + if (err) + goto out_end_trans; + + /* + * This will help us catch people modifying the fs tree while we're + * dropping it. It is unsafe to mess with the fs tree while it's being + * dropped as we unlock the root node and parent nodes as we walk down + * the tree, assuming nothing will change. If something does change + * then we'll have stale information and drop references to blocks we've + * already dropped. + */ + set_bit(BTRFS_ROOT_DELETING, &root->state); + if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) { + level = btrfs_header_level(root->node); + path->nodes[level] = btrfs_lock_root_node(root); + btrfs_set_lock_blocking_write(path->nodes[level]); + path->slots[level] = 0; + path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING; + memset(&wc->update_progress, 0, + sizeof(wc->update_progress)); + } else { + btrfs_disk_key_to_cpu(&key, &root_item->drop_progress); + memcpy(&wc->update_progress, &key, + sizeof(wc->update_progress)); + + level = root_item->drop_level; + BUG_ON(level == 0); + path->lowest_level = level; + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + path->lowest_level = 0; + if (ret < 0) { + err = ret; + goto out_end_trans; + } + WARN_ON(ret > 0); + + /* + * unlock our path, this is safe because only this + * function is allowed to delete this snapshot + */ + btrfs_unlock_up_safe(path, 0); + + level = btrfs_header_level(root->node); + while (1) { + btrfs_tree_lock(path->nodes[level]); + btrfs_set_lock_blocking_write(path->nodes[level]); + path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING; + + ret = btrfs_lookup_extent_info(trans, fs_info, + path->nodes[level]->start, + level, 1, &wc->refs[level], + &wc->flags[level]); + if (ret < 0) { + err = ret; + goto out_end_trans; + } + BUG_ON(wc->refs[level] == 0); + + if (level == root_item->drop_level) + break; + + btrfs_tree_unlock(path->nodes[level]); + path->locks[level] = 0; + WARN_ON(wc->refs[level] != 1); + level--; + } + } + + wc->restarted = test_bit(BTRFS_ROOT_DEAD_TREE, &root->state); + wc->level = level; + wc->shared_level = -1; + wc->stage = DROP_REFERENCE; + wc->update_ref = update_ref; + wc->keep_locks = 0; + wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info); + + while (1) { + + ret = walk_down_tree(trans, root, path, wc); + if (ret < 0) { + err = ret; + break; + } + + ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL); + if (ret < 0) { + err = ret; + break; + } + + if (ret > 0) { + BUG_ON(wc->stage != DROP_REFERENCE); + break; + } + + if (wc->stage == DROP_REFERENCE) { + wc->drop_level = wc->level; + btrfs_node_key_to_cpu(path->nodes[wc->drop_level], + &wc->drop_progress, + path->slots[wc->drop_level]); + } + btrfs_cpu_key_to_disk(&root_item->drop_progress, + &wc->drop_progress); + root_item->drop_level = wc->drop_level; + + BUG_ON(wc->level == 0); + if (btrfs_should_end_transaction(trans) || + (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) { + ret = btrfs_update_root(trans, tree_root, + &root->root_key, + root_item); + if (ret) { + btrfs_abort_transaction(trans, ret); + err = ret; + goto out_end_trans; + } + + btrfs_end_transaction_throttle(trans); + if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) { + btrfs_debug(fs_info, + "drop snapshot early exit"); + err = -EAGAIN; + goto out_free; + } + + /* + * Use join to avoid potential EINTR from transaction + * start. See wait_reserve_ticket and the whole + * reservation callchain. + */ + if (for_reloc) + trans = btrfs_join_transaction(tree_root); + else + trans = btrfs_start_transaction(tree_root, 0); + if (IS_ERR(trans)) { + err = PTR_ERR(trans); + goto out_free; + } + } + } + btrfs_release_path(path); + if (err) + goto out_end_trans; + + ret = btrfs_del_root(trans, &root->root_key); + if (ret) { + btrfs_abort_transaction(trans, ret); + err = ret; + goto out_end_trans; + } + + if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) { + ret = btrfs_find_root(tree_root, &root->root_key, path, + NULL, NULL); + if (ret < 0) { + btrfs_abort_transaction(trans, ret); + err = ret; + goto out_end_trans; + } else if (ret > 0) { + /* if we fail to delete the orphan item this time + * around, it'll get picked up the next time. + * + * The most common failure here is just -ENOENT. + */ + btrfs_del_orphan_item(trans, tree_root, + root->root_key.objectid); + } + } + + /* + * This subvolume is going to be completely dropped, and won't be + * recorded as dirty roots, thus pertrans meta rsv will not be freed at + * commit transaction time. So free it here manually. + */ + btrfs_qgroup_convert_reserved_meta(root, INT_MAX); + btrfs_qgroup_free_meta_all_pertrans(root); + + if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) + btrfs_add_dropped_root(trans, root); + else + btrfs_put_root(root); + root_dropped = true; +out_end_trans: + btrfs_end_transaction_throttle(trans); +out_free: + kfree(wc); + btrfs_free_path(path); +out: + /* + * So if we need to stop dropping the snapshot for whatever reason we + * need to make sure to add it back to the dead root list so that we + * keep trying to do the work later. This also cleans up roots if we + * don't have it in the radix (like when we recover after a power fail + * or unmount) so we don't leak memory. + */ + if (!for_reloc && !root_dropped) + btrfs_add_dead_root(root); + return err; +} + +/* + * drop subtree rooted at tree block 'node'. + * + * NOTE: this function will unlock and release tree block 'node' + * only used by relocation code + */ +int btrfs_drop_subtree(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct extent_buffer *node, + struct extent_buffer *parent) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_path *path; + struct walk_control *wc; + int level; + int parent_level; + int ret = 0; + int wret; + + BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID); + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + wc = kzalloc(sizeof(*wc), GFP_NOFS); + if (!wc) { + btrfs_free_path(path); + return -ENOMEM; + } + + btrfs_assert_tree_locked(parent); + parent_level = btrfs_header_level(parent); + atomic_inc(&parent->refs); + path->nodes[parent_level] = parent; + path->slots[parent_level] = btrfs_header_nritems(parent); + + btrfs_assert_tree_locked(node); + level = btrfs_header_level(node); + path->nodes[level] = node; + path->slots[level] = 0; + path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING; + + wc->refs[parent_level] = 1; + wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF; + wc->level = level; + wc->shared_level = -1; + wc->stage = DROP_REFERENCE; + wc->update_ref = 0; + wc->keep_locks = 1; + wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info); + + while (1) { + wret = walk_down_tree(trans, root, path, wc); + if (wret < 0) { + ret = wret; + break; + } + + wret = walk_up_tree(trans, root, path, wc, parent_level); + if (wret < 0) + ret = wret; + if (wret != 0) + break; + } + + kfree(wc); + btrfs_free_path(path); + return ret; +} + +/* + * helper to account the unused space of all the readonly block group in the + * space_info. takes mirrors into account. + */ +u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo) +{ + struct btrfs_block_group *block_group; + u64 free_bytes = 0; + int factor; + + /* It's df, we don't care if it's racy */ + if (list_empty(&sinfo->ro_bgs)) + return 0; + + spin_lock(&sinfo->lock); + list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) { + spin_lock(&block_group->lock); + + if (!block_group->ro) { + spin_unlock(&block_group->lock); + continue; + } + + factor = btrfs_bg_type_to_factor(block_group->flags); + free_bytes += (block_group->length - + block_group->used) * factor; + + spin_unlock(&block_group->lock); + } + spin_unlock(&sinfo->lock); + + return free_bytes; +} + +int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info, + u64 start, u64 end) +{ + return unpin_extent_range(fs_info, start, end, false); +} + +/* + * It used to be that old block groups would be left around forever. + * Iterating over them would be enough to trim unused space. Since we + * now automatically remove them, we also need to iterate over unallocated + * space. + * + * We don't want a transaction for this since the discard may take a + * substantial amount of time. We don't require that a transaction be + * running, but we do need to take a running transaction into account + * to ensure that we're not discarding chunks that were released or + * allocated in the current transaction. + * + * Holding the chunks lock will prevent other threads from allocating + * or releasing chunks, but it won't prevent a running transaction + * from committing and releasing the memory that the pending chunks + * list head uses. For that, we need to take a reference to the + * transaction and hold the commit root sem. We only need to hold + * it while performing the free space search since we have already + * held back allocations. + */ +static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed) +{ + u64 start = SZ_1M, len = 0, end = 0; + int ret; + + *trimmed = 0; + + /* Discard not supported = nothing to do. */ + if (!blk_queue_discard(bdev_get_queue(device->bdev))) + return 0; + + /* Not writable = nothing to do. */ + if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state)) + return 0; + + /* No free space = nothing to do. */ + if (device->total_bytes <= device->bytes_used) + return 0; + + ret = 0; + + while (1) { + struct btrfs_fs_info *fs_info = device->fs_info; + u64 bytes; + + ret = mutex_lock_interruptible(&fs_info->chunk_mutex); + if (ret) + break; + + find_first_clear_extent_bit(&device->alloc_state, start, + &start, &end, + CHUNK_TRIMMED | CHUNK_ALLOCATED); + + /* Check if there are any CHUNK_* bits left */ + if (start > device->total_bytes) { + WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG)); + btrfs_warn_in_rcu(fs_info, +"ignoring attempt to trim beyond device size: offset %llu length %llu device %s device size %llu", + start, end - start + 1, + rcu_str_deref(device->name), + device->total_bytes); + mutex_unlock(&fs_info->chunk_mutex); + ret = 0; + break; + } + + /* Ensure we skip the reserved area in the first 1M */ + start = max_t(u64, start, SZ_1M); + + /* + * If find_first_clear_extent_bit find a range that spans the + * end of the device it will set end to -1, in this case it's up + * to the caller to trim the value to the size of the device. + */ + end = min(end, device->total_bytes - 1); + + len = end - start + 1; + + /* We didn't find any extents */ + if (!len) { + mutex_unlock(&fs_info->chunk_mutex); + ret = 0; + break; + } + + ret = btrfs_issue_discard(device->bdev, start, len, + &bytes); + if (!ret) + set_extent_bits(&device->alloc_state, start, + start + bytes - 1, + CHUNK_TRIMMED); + mutex_unlock(&fs_info->chunk_mutex); + + if (ret) + break; + + start += len; + *trimmed += bytes; + + if (fatal_signal_pending(current)) { + ret = -ERESTARTSYS; + break; + } + + cond_resched(); + } + + return ret; +} + +/* + * Trim the whole filesystem by: + * 1) trimming the free space in each block group + * 2) trimming the unallocated space on each device + * + * This will also continue trimming even if a block group or device encounters + * an error. The return value will be the last error, or 0 if nothing bad + * happens. + */ +int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range) +{ + struct btrfs_block_group *cache = NULL; + struct btrfs_device *device; + struct list_head *devices; + u64 group_trimmed; + u64 range_end = U64_MAX; + u64 start; + u64 end; + u64 trimmed = 0; + u64 bg_failed = 0; + u64 dev_failed = 0; + int bg_ret = 0; + int dev_ret = 0; + int ret = 0; + + /* + * Check range overflow if range->len is set. + * The default range->len is U64_MAX. + */ + if (range->len != U64_MAX && + check_add_overflow(range->start, range->len, &range_end)) + return -EINVAL; + + cache = btrfs_lookup_first_block_group(fs_info, range->start); + for (; cache; cache = btrfs_next_block_group(cache)) { + if (cache->start >= range_end) { + btrfs_put_block_group(cache); + break; + } + + start = max(range->start, cache->start); + end = min(range_end, cache->start + cache->length); + + if (end - start >= range->minlen) { + if (!btrfs_block_group_done(cache)) { + ret = btrfs_cache_block_group(cache, 0); + if (ret) { + bg_failed++; + bg_ret = ret; + continue; + } + ret = btrfs_wait_block_group_cache_done(cache); + if (ret) { + bg_failed++; + bg_ret = ret; + continue; + } + } + ret = btrfs_trim_block_group(cache, + &group_trimmed, + start, + end, + range->minlen); + + trimmed += group_trimmed; + if (ret) { + bg_failed++; + bg_ret = ret; + continue; + } + } + } + + if (bg_failed) + btrfs_warn(fs_info, + "failed to trim %llu block group(s), last error %d", + bg_failed, bg_ret); + mutex_lock(&fs_info->fs_devices->device_list_mutex); + devices = &fs_info->fs_devices->devices; + list_for_each_entry(device, devices, dev_list) { + if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state)) + continue; + + ret = btrfs_trim_free_extents(device, &group_trimmed); + if (ret) { + dev_failed++; + dev_ret = ret; + break; + } + + trimmed += group_trimmed; + } + mutex_unlock(&fs_info->fs_devices->device_list_mutex); + + if (dev_failed) + btrfs_warn(fs_info, + "failed to trim %llu device(s), last error %d", + dev_failed, dev_ret); + range->len = trimmed; + if (bg_ret) + return bg_ret; + return dev_ret; +} |